[llvm] [workflows] Add a new workflow for checking commit access qualifications (PR #93301)

[Tom Stellard via llvm-commits]

tstellar wrote:

> * Do you have numbers on how many API requests this uses? At a quick glance I would expect it to use quite a bit. If it's under the `RELEASE_TASKS_USER_TOKEN`, it might be fine though?

It uses between 3,000 and 4,000 API calls typically, depending on how many users there are.

https://github.com/llvm/llvm-project/pull/93301