Update code to match changes in firebase/firebase-ios-sdk#9101

Author: peterfriese

FirestoreCodableSamples.xcodeproj/project.pbxproj

@@ -60,6 +60,7 @@
 		887A4A7F2608EA7E009ACBB1 /* MappingEnumsScreen.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MappingEnumsScreen.swift; sourceTree = "<group>"; };
 		887DD2B325C47A23003F7A99 /* Book.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Book.swift; sourceTree = "<group>"; };
 		888F881325C46A9C00DCE039 /* GoogleService-Info.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = "GoogleService-Info.plist"; sourceTree = "<group>"; };
+		88BBF4452790B29800A6D1A7 /* firebase-ios-sdk */ = {isa = PBXFileReference; lastKnownFileType = wrapper; name = "firebase-ios-sdk"; path = "../../../Projects/Incubation/Firebase/firebase-documentsnapshot-typing/firebase-ios-sdk"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -78,6 +79,7 @@
 		8845BD6D25C46965002AEC45 = {
 			isa = PBXGroup;
 			children = (
+				88BBF4442790B29800A6D1A7 /* Packages */,
 				8845BD7825C46965002AEC45 /* FirestoreCodableSamples */,
 				8845BD7725C46965002AEC45 /* Products */,
 				887DD2AD25C479FD003F7A99 /* Frameworks */,
@@ -178,6 +180,14 @@
 			path = ViewModels;
 			sourceTree = "<group>";
 		};
+		88BBF4442790B29800A6D1A7 /* Packages */ = {
+			isa = PBXGroup;
+			children = (
+				88BBF4452790B29800A6D1A7 /* firebase-ios-sdk */,
+			);
+			name = Packages;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXNativeTarget section */

FirestoreCodableSamples/Screens/CustomizeMappingScreen.swift

@@ -38,17 +38,9 @@ class CustomizeMappingViewModel: ObservableObject {
 
             switch result {
             case .success(let programmingLanguage):
-              if let programmingLanguage = programmingLanguage {
-                // A ProgrammingLanguage value was successfully initialized from the DocumentSnapshot.
-                self?.errorMessage = nil
-                return programmingLanguage
-              }
-              else {
-                // A nil value was successfully initialized from the DocumentSnapshot,
-                // or the DocumentSnapshot was nil.
-                self?.errorMessage = "Document doesn't exist."
-                return nil
-              }
+              // A ProgrammingLanguage value was successfully initialized from the DocumentSnapshot.
+              self?.errorMessage = nil
+              return programmingLanguage
             case .failure(let error):
               // A Book value could not be initialized from the DocumentSnapshot.
               switch error {

FirestoreCodableSamples/Screens/MappingColorsScreen.swift

@@ -35,22 +35,13 @@ class MappingColorsViewModel: ObservableObject {
 
           self?.colorEntries = documents.compactMap { queryDocumentSnapshot in
             let result = Result { try queryDocumentSnapshot.data(as: ColorEntry.self) }
-            
             switch result {
             case .success(let colorEntry):
-              if let colorEntry = colorEntry {
-                // A ColorEntry value was successfully initialized from the DocumentSnapshot.
-                self?.errorMessage = nil
-                return colorEntry
-              }
-              else {
-                // A nil value was successfully initialized from the DocumentSnapshot,
-                // or the DocumentSnapshot was nil.
-                self?.errorMessage = "Document doesn't exist."
-                return nil
-              }
+              // A ColorEntry value was successfully initialized from the DocumentSnapshot.
+              self?.errorMessage = nil
+              return colorEntry
             case .failure(let error):
-              // A Book value could not be initialized from the DocumentSnapshot.
+              // A ColorEntry value could not be initialized from the DocumentSnapshot.
               switch error {
               case DecodingError.typeMismatch(_, let context):
                 self?.errorMessage = "\(error.localizedDescription): \(context.debugDescription)"

FirestoreCodableSamples/Screens/MappingEnumsScreen.swift

@@ -76,17 +76,9 @@ class MappingEnumsViewModel: ObservableObject {
 
             switch result {
             case .success(let article):
-              if let article = article {
-                // An Article value was successfully initialized from the DocumentSnapshot.
-                self?.errorMessage = nil
-                return article
-              }
-              else {
-                // A nil value was successfully initialized from the DocumentSnapshot,
-                // or the DocumentSnapshot was nil.
-                self?.errorMessage = "Document doesn't exist."
-                return nil
-              }
+              // An Article value was successfully initialized from the DocumentSnapshot.
+              self?.errorMessage = nil
+              return article
             case .failure(let error):
               // An Article value could not be initialized from the DocumentSnapshot.
               switch error {

FirestoreCodableSamples/Screens/MappingGeoPointsScreen.swift

@@ -82,17 +82,9 @@ class MappingGeoPointsViewModel: ObservableObject {
 
             switch result {
             case .success(let office):
-              if let office = office {
-                // An Office value was successfully initialized from the DocumentSnapshot.
-                self?.errorMessage = nil
-                return office
-              }
-              else {
-                // A nil value was successfully initialized from the DocumentSnapshot,
-                // or the DocumentSnapshot was nil.
-                self?.errorMessage = "Document doesn't exist."
-                return nil
-              }
+              // An Office value was successfully initialized from the DocumentSnapshot.
+              self?.errorMessage = nil
+              return office
             case .failure(let error):
               // An Office value could not be initialized from the DocumentSnapshot.
               switch error {