Remove gitlab_shell_jwt_token feature flag
What does this MR do and why?
The feature flag has been enabled for a while. It also has been enabled by default in the previous release, so the self-managed will be able to turn it off if it doesn't work for their setups: !100929 (merged)
Introduced in: !86148 (merged)
Rollout issue: #360808 (closed)
Edited by Igor Drozdov