[New Feature]: Try manual merge if automerge feature fails automatically

### Description of the new feature/enhancement

Maybe we should configure the bot to be able to manually merge PR in cases where https://github.com/microsoft/winget-pkgs/labels/Validation-Completed is assigned but automerge fails, utilizing https://github.com/microsoft/winget-pkgs/labels/Needs-Manual-Merge label or something.
So there has to be a way to detect if themselves caught in a loop such as this:

If so, assign that manual merge label and that label event listener will eventually merge that PR even without automerge.

This is an extension of long-standing issues: #409875 #142854

### Proposed technical implementation details (optional)

_No response_

Start by reviewing issues #409875 and #142854, then inspect how the Validation-Completed and Needs-Manual-Merge labels are handled. The change is done when an automerge failure loop is detected, Needs-Manual-Merge is assigned, and the label event listener can merge the pull request.

Written by the indexing model from the issue text.