Issue Summary

When removing a user from the "Merge via pull requests" permission using the API, if you click on the edit button, you will see the user still populated there.

Steps to Reproduce

1. Create a branch restriction
2. Add the same user to "Merge via pull requests" and "Write access"
3. Use the API to remove the user from "Merge via pull requests" using the following example body:

   {
       "kind": "restrict_merges",
       "type": "branchrestriction",
       "pattern": "main"
   }
   

1. Observe in the UI that the "Merge via pull requests" will have a value of none.
2. Click on the "edit" button

Expected Results

The expected is to see the field empty

Actual Results

The removed user will still appear, but grayed out.

Workaround

This is just a UI bug, it doesn't affect functionality and the removed user won't be able to merge any PRs.