test: Add visibility configuration tests; verify default and overridden settings

[iqbalhasandev]

This pull request enhances the Filex library by introducing support for file visibility parameters (public and private) and adding corresponding convenience methods for file operations. Additionally, it includes new unit tests to ensure the functionality and configuration of visibility settings.

Enhancements to file visibility:

• tests/Unit/FilexTest.php: Added tests for moveFile and moveFiles with explicit visibility parameters (public and private). Also introduced convenience methods (moveFilePublic, moveFilePrivate, moveFilesPublic, and moveFilesPrivate) and their respective tests. [1] [2] [3] [4]

Updates to HasFilex trait:

• tests/Unit/Traits/HasFilexTest.php: Modified moveFilePublic and moveFilesPublic methods to include visibility parameters. Added exposed methods (moveFilePublicExposed, moveFilePrivateExposed, etc.) for testing convenience methods. [1] [2]

New visibility configuration tests:

• tests/Unit/VisibilityConfigTest.php: Added tests for default visibility configuration, overriding visibility settings, and validating supported visibility options (public and private).