Replication of original PR #596: Update PEP 649/749 implementation

[yashwanthatla]

PR Summary

Update Forward Reference Evaluation for Python 3.14+ Compatibility

Overview

This PR updates the forward reference evaluation mechanism to ensure compatibility with Python 3.14+ by replacing runtime detection of PEP 649/749 implementation with version-based checks.

Change Types

Type	Description
Enhancement	Update forward reference handling for Python 3.14+ compatibility
Refactor	Replace feature detection with version-based checks

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Affected Modules

Module / File	Change Description
typing_extensions.py	Changed default parameter value in evaluate_forward_ref function from Format.VALUE to None
typing_extensions.py	Replaced runtime detection of PEP 649/749 with version-based import approach
test_typing_extensions.py	Updated tests to use explicit version checks instead of feature detection