* Return nicer error if trying to pull from non-existent user
Gitea serv will currently return an 500 if we try to pull from a repository where
the owner does not exist.
This PR checks for the UserNotExist Error when checking for the user and will
return a NotFound error instead.
Fix#18225
log.Error("Failed authentication attempt for %s with key %s (not authorized to %s %s/%s) from %s",user.Name,key.Name,modeString,ownerName,repoName,ctx.RemoteAddr())
log.Warn("Failed authentication attempt for %s with key %s (not authorized to %s %s/%s) from %s",user.Name,key.Name,modeString,ownerName,repoName,ctx.RemoteAddr())