[24.0] Follow-up on #18212

[nsoranzo]

Two GitHub actions fixes:

• Fix the milestone not being added to pull requests due to missing issues: write permission
• Fix area/UI-UX label being added to unrelated pull requests

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[nsoranzo]

Unfortunately changes will take effect only once this PR is merged.