BUG: Push rules are not respected on fast-forward merge
### Summary
Push rules (commit messages regex) are not respected on fast-forward merge.
### Steps to reproduce
- Create a new repository
- Add a regex push rule (Settings/Repository/Push Rules)
- Select fast-forward merge (Setting/General/Merge Request/Merge Method)
- Fork your repository (The push rule is not propagated)
- Make a merge request with a bad commit message
- Approve the Merge request
### What is the current *bug* behavior?
Commit that are not respecting the push rule are allowed
### What is the expected *correct* behavior?
Commit that are not respecting the push rule are not allowed
issue