Fix issue labeler permissions and regex

[stampyzfanz]

Fixed 2 bugs found by @Qianqianye in #5731 (comment)

Changes:

1. The regex was relaxed to allow capital and lowercase Xs in the checkboxes and allow arbitrary whitespace between them and the issue name because issue forms have inconsistent markdown for some reason. Qianqianye noticed that Test issue labeler #5741 didn't product expected results which has been fixed in my fork.
2. The write permission was granted to the workflow using the permissions key so that it can actually add the label. This was only added to the labeler workflow and should not impede the security of any other GitHub Actions.

Something else I noticed was a warning in the GitHub Action from the use of an undefined key enable-versioned-regex, however, the key is reccomended by the docs. Additionally, it still ends in an error message which is a known bug. However, it still works as expected and can label issues in my fork even after I reduced the permissions of the GITHUB_TOKEN to try to emulate this repository.

Just let me know if I should create an issue for this.

Screenshots of the change:

PR Checklist

• npm run lint passes
• Inline documentation is included / updated
• Unit tests are included / updated

[Qianqianye]

Thank you @stampyzfanz! I did a test in issue #5745 and the labels totally worked. Thanks!