Post V1/V2 API endpoint refactor cleanup

[Sepehr-Sobhani]

Describe the task

The pull request to separate the V1 and V2 endpoints was already quite large, so this ticket addresses some remaining parts that were not tied to the actual refactor, focusing on enhancements to improve code readability.

Acceptance Criteria

• Use proper API tags for V1 and V2 endpoints (separate tags per module and API version like USER_OPERATOR_TAGS for V2 and USER_OPERATOR_TAGS_V1 for V1)
• Implement test in bc_obps/registration/tests/endpoints/v2/user/test_user_app_role.py