Every time we do a CheckRun on a backport PR, we search the forge for the actual commit of for the original hash. On GitLab, this search is rather inefficient as it will go through every repository in the configured list of groups. As this list grows over time, this search becomes increasingly time consuming.

To alleviate this, we should at least make sure to cache the result, by which I mean the repository we found the commit in, together with the hash in an MR comment so we only need to perform the search once.