ci: fix labeler

[holmanb]

Proposed Commit Message

ci: fix labeler

Additional Context

The failed job shows this output:

Run actions/labeler@v5
  with:
    repo-token: ***
    configuration-path: .github/labeler.yml
    sync-labels: false
    dot: true
The configuration file (path: .github/labeler.yml) was not found locally, fetching via the api
Error: SyntaxError: Invalid regular expression: /ubuntu/**/: Nothing to repeat
Error: Invalid regular expression: /ubuntu/**/: Nothing to repeat

This PR removes the offending line, which was redundant anyways

So I'm not really sure how to test this, because unlike normal workflows, the base branch runs the labeler job. Per the docs:

When submitting an initial pull request to a repository using the pull_request_target event, the labeler workflow will not run on that pull request because the pull_request_target execution runs off the base branch instead of the pull request's branch

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[blackboxsw]

Shipit, test run against a non ubuntu/* base-branch succeeds once this lands.