[llvm] workflows/commit-access-review: Use a GitHub App access token instead of llvmbot (PR #179364)

[Tom Stellard via llvm-commits]

tstellar wrote:

The tokens are only good for 1 hour, so we need to merge https://github.com/llvm/llvm-project/pull/181204 first in order to drop the run time of the script under 1 hour.

https://github.com/llvm/llvm-project/pull/179364