[Regression] Maintainers prematurely blocked from asssigning compliance frameworks

Summary

• Raised via QA issue: https://gitlab.com/gitlab-org/release/tasks/-/issues/2218
• Maintainers should not be blocked from assigning compliance frameworks to projects until ff_custom_compliance_frameworks is enabled.

Steps to reproduce

• Login as a project maintainer
• Attempt to assign compliance framework to a project
• Notice that the assignment has not happened