Editing the required approvers on a merge request does not work

Summary

Editing the required approvers on a merge request does not work.

Steps to reproduce

1. Edit a merge request which has 0 required approvers
2. Change required approvers to 1
3. Save

What is the current bug behavior?

Required Approvers is still 0, Merge button is enabled.

What is the expected correct behavior?

Required Approvers is set to 1, Merge button is disabled until approval requirements are met

Relevant logs and/or screenshots

(Paste any relevant logs - please use code blocks (```) to format console output, logs, and code as it's very hard to read otherwise.)

Output of checks

This bug happens on GitLab.com