Bedevere no longer comments on PRs that break stable buildbots

Bedevere used to comment on PRs that break stable buildbots, e.g. https://github.com/python/cpython/pull/17975#issuecomment-830911179 .

It seems like the feature no longer works. For example PR https://github.com/python/cpython/pull/94549 broke four stable [WebAssembly buildbots](https://buildbot.python.org/all/#/builders?tags=%2Bwasm) but bedever-bot did not add a warning to the PR.