Address old and potentially unused Feature Flags linked to our team

In #373936 (comment 1182885538), we identified a number of Feature Flags that should be reviewed:

These are :ops, and dynamically constructed using the class name:

• gitlab_service_measuring_projects_create_service
• gitlab_service_measuring_projects_import_export_export_service
• gitlab_service_measuring_projects_import_service

This one was discussed to be converted to :ops:

• ci_register_job_temporary_lock