Ignore readOnly/writeOnly set to False

[p1c2u]

This pull request improves the handling of readOnly and writeOnly properties in the OpenAPI schema validator. It ensures that properties explicitly set to False for these keywords are correctly ignored during validation, and adds tests to verify this behavior.

Validation logic improvements:

• Updated the write_readOnly function in openapi_schema_validator/_keywords.py to immediately return if the readOnly flag is not set, preventing unnecessary validation errors when readOnly is False.
• Updated the read_writeOnly function in openapi_schema_validator/_keywords.py to immediately return if the writeOnly flag is not set, preventing unnecessary validation errors when writeOnly is False.

Testing enhancements:

• Added test_read_only_false and test_write_only_false to tests/integration/test_validators.py to ensure that properties with readOnly: False or writeOnly: False are validated without errors.