Update PR migration warning workflow to skip PRs where the label was manually removed

[martygrant]

Noticed on some PRs (#2733) the label was manually removed but the automation added this back in. This was handled in an earlier version of the script where the action was triggered by PR events and would not be triggered by labeling events so authors could manually remove the label and the action would not re-add it.

The script was modified to run on a schedule and check all open PRs. This change specifically checks if the PR has had the label added in the past, and skips if true, avoiding the unnecessary re-labeling.

[github-actions]

Unified Runtime -> intel/llvm Repo Move Notice

Information

The source code of Unified Runtime has been moved to intel/llvm under the unified-runtime top-level directory,
all future development will now be carried out there. This was done in intel/llvm#17043.

The code will be mirrored to oneapi-src/unified-runtime and the specification will continue to be hosted at oneapi-src.github.io/unified-runtime.

The contribution guide will be updated with new instructions for contributing to Unified Runtime.

PR Migration

All open PRs including this one will be marked with the auto-close label and shall be automatically closed after 30 days.

Should you wish to continue with your PR you will need to migrate it to intel/llvm.
We have provided a script to help automate this process.

If your PR should remain open and not be closed automatically, you can remove the auto-close label.

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This is an automated comment.