The reformat action should check the source repo for permissions

Currently, it is master in the target repo or the submitter. Instead, we should check for some minimum level of permission for the source repository as well. This happens when one developer submits an MR, hands it off to another via access to the original source repo and then the reformat action is denied.

As a workaround, using a new MR is viable.

Cc: @brad.king