[llvm] [CI] Make premerge advisor requests fail open (PR #224861)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

> Not to point fingers, but are we doing any tracking of test flakiness?

I added an endpoint to the premerge advisor that should expose this info, but have never acted upon it.

https://github.com/llvm/llvm-project/pull/224861