I04 XRC: Improve ispyb comment when no diffraction found

Currently, if we find no diffraction when doing an XRC we put a comment in ispyb of "Diffraction not found, skipping sample.". This makes sense in a UDC context as we are skipping the sample but when the XRC is being manually triggered it no longer makes sense. We should check with @aragaod but we probably just want to leave it at "Diffraction not found".

## Acceptance Criteria
- ispyb comment makes more sense when no diffraction found during manually triggered XRC
- Comment is unchanged in Hyperion UDC