Fix `abs` and `round` calls in the codebase with test coverage

[andrewbess]

Description (*)

The call of the functions abs and round with param that is different from int|float types provokes next problems:

• Deprecated: abs(): Passing null to parameter #1 ($num) of type int|float is deprecated - if null param has been provided in PHP >= 8.1
• Fatal error: Uncaught TypeError: abs(): Argument #1 ($num) must be of type int|float, string given - if empty string provided as param in PHP >= 8.0.
  We need to fix these problems in codebase.
  Also, we need coverage of the changed functionality with unit or integration tests.

[m2-assistant]

Hi @andrewbess. Thank you for your report.
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