[Issue] [ReadMe] updated readMe file for GraphQl-GroupedProductGraphQl modules

[m2-assistant]

This issue is automatically created based on existing pull request: #31810: [ReadMe] updated readMe file for GraphQl-GroupedProductGraphQl modules

DevDoc related issue: magento/devdocs#4451

---

Description (*)

Update README.md file for modules:

• Magento_GraphQl
• Magento_GraphQlCache
• Magento_GroupedCatalogInventory
• Magento_GroupedImportExport
• Magento_GroupedProduct
• Magento_GroupedProductGraphQl

Fixed Issues (if relevant)

1. README content for modules - work in M2 Code devdocs#4451 README content for modules - work in M2 Code

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds are green)