In the method GitLabMergeRequest::author, the author of an MR is looked up in the forge. If this returns an empty Optional, all we get is an error message that says "No value present". I think we can do better and add something that explains which username we failed to look up.

This seems to happen when users are made inactive, but still have open MRs, and it would be good if an admin could easily identify what was happening so that the correct action can be performed.