Branch permission pattern with backslash break the settings

Summary

If branch permission with backslash ( \ ) is mistakenly created, none of the existing branch permissions in the repository or project can be edited anymore.

Steps to Reproduce

1. Create a few branch permissions in the repository or project
2. Create a branch permission with pattern "release\" (backslash instead forward slash)
3. Save the setting
   It will take some time for the page to reload
4. Try to create a new or edit other branch permissions

Expected Results

1. The incorrect branch permission with the pattern "release\" will not be saved
2. Can create and edit other branch permissions

Actual Results

1. The incorrect branch permission with the pattern "release\" does not appear in the list but the database table "AO_6978BB_RESTRICTED_REF" have this setting
2. Can't create and edit other branch permissions
3. The below exception is thrown in the browser Console:

   Uncaught Error: Syntax error, unrecognized expression: tbody[data-branch-value="release\"][data-branch-type="PATTERN"][data-effective-scope-type="REPOSITORY"]
   

Workaround

1. Retrieve branch permissions via REST to find the ID (should be a number) of the offending permission:

   curl -v -H "Accept:application/json" <USERNAME>:<PASSWORD>@<INSTANCE_URL>/rest/branch-permissions/latest/projects/<PROJECT_KEY>/repos/<REPO_SLUG>/restrictions/

   If you have Python installed you can append the following to this command to make the output more readable:

   | python -m json.tool

2. Delete the offending permission via REST:

   curl -v -X DELETE <USERNAME>:<PASSWORD>@<INSTANCE_URL>/rest/branch-permissions/latest/projects/<PROJECT_KEY>/repos/<REPO_SLUG>/restrictions/<PERMISSION_ID>
   

3. Verify the permission has been deleted by repeating step 1.