[llvm] [pr-subscribers] added `third-party:benchmark` to `new-prs-labeler` (PR #83486)

[Tom Stellard via llvm-commits]

https://github.com/tstellar approved this pull request.

Team Created: https://github.com/orgs/llvm/teams/pr-subscribers-third-party-benchmark/members

https://github.com/llvm/llvm-project/pull/83486