[Validation Issue]: Pipelines are not validating Merge Conflicts

### Please confirm these before moving forward

- [x] I have searched for my issue and not found a work-in-progress/duplicate/resolved issue.
- [x] I have not been informed if the issue is resolved in a preview version of the winget client.

### Category of the issue

Other

### Brief description of your issue

When a PR has merge conflicts, wingetbot will repeatedly trigger `@wingetbot run` - however, the pipeline never runs.

See https://github.com/microsoft/winget-pkgs/pull/373628

### Steps to reproduce

Create a PR with merge conflicts

### Actual behavior

Validation never runs and the PR repeatedly gets commented on by Wingetbot

### Expected behavior

1. Wingetbot to not comment repeatedly
2. The pipelines to be run and apply https://github.com/microsoft/winget-pkgs/labels/Validation-Merge-Conflict -OR- the label to be applied by wingetbot

### Environment

```raw
winget-pkgs repo
```

### Screenshots and Logs

_No response_

Start with pull request 373628 and reproduce the merge-conflict state, then trace how `@wingetbot run` interacts with validation pipelines and the `Validation-Merge-Conflict` label. Done means validation runs or the label is applied, and Wingetbot no longer posts repeated comments.

Written by the indexing model from the issue text.