I recently received a minor revision decision in the first round of review from a top journal with a strict review process. I forgot to add my cover letter to the submission. It wasn’t among the mandatory files so their submission portal allowed me to submit the revision without a cover letter. There was nothing in the cover letter except thanking the editor and saying that we have addresses all the comments in the response document and the revised manuscript. Shall I send the cover letter separately as a message/email via their communication system or it’s not needed?