Integration test coverage for feature freezing

[bedeho]

Background

• https://github.com/Joystream/joystream/issues/4897
• https://github.com/Joystream/joystream/issues/4898

Proposal

Add basic test similar to other proposals, where it is tested that CRTs are indeed no longer working after the proposal

┆Issue is synchronized with this Asana task by Unito