fix(phpstan): improve function calls and add type checks

This commit addresses several improvements including procedural changes in code, better function calls, added type checks, and cleanup of redundant tags. Also, it introduces a more pythonic approach in the VerificationFactory and VerificationRepository classes. It verifies if specific methods exist before invocation to prevent possible errors. It updates the handling method in the Verifier class and makes sure the class exists before the operation in PhoneNumberViaSmsPhoneVerifier and PhoneNumberViaVoiceCallPhoneVerifier. Finally, it cleans up unused tags and refactors PHPDocs in various files for better readability.

Related: #6 (closed)