Prevent "Move labelled issues to correct projects" GitHub Actions workflow from failing when an issue is already on the project board

[anoadragon453]

The "Move labelled issues to correct projects" exists to move issues to the "Needs info" column on our internal triage queue GitHub project board when the X-Needs-Info label is added to it.

The workflow will currently fail if the issue is already on the project board (which is most of the time).

This change will prevent the workflow from failing in this case - instead carrying on even if the "actions/add-to-project" step failed.

Ideally there would be a "no-op option" on the "add-to-project" action so we didn't have to ignore any other failures as well, but alas, there is not. Still, if the issue failed to be added to the project, then the subsequent step will fail anyways (as the issue is not on the project).

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file. The entry should:
  • Be a short description of your change which makes sense to users. "Fixed a bug that prevented receiving messages from other servers." instead of "Moved X method from EventStore to EventWorkerStore.".
  • Use markdown where necessary, mostly for code blocks.
  • End with either a period (.) or an exclamation mark (!).
  • Start with a capital letter.
  • Feel free to credit yourself, by adding a sentence "Contributed by @github_username." or "Contributed by [Your Name]." to the end of the entry.
• Code style is correct (run the linters)