Bring back the "Regenerate SSH key" button for repo mirrors

From a Slack conversation (internal):

Hi team, I have a question here. People who were working on the file I’m interested in are not at GitLab anymore or at the moment. So I’m asking here. In this commit fb50fa48 I’m interested in a single line which removes = render 'projects/mirrors/regenerate_public_ssh_key_confirm_modal. It looks like this template is not used anymore and just was not deleted. Or is it still needed? Could anyone confirm that it is really not used and I’ll proceed with removing the file.

stanhu 24 hours ago Yeah, I don't see that file being referenced at all. I thought we had the ability to regenerate the public key of a mirror for a reason. Do we no longer?

mkozono 23 hours ago That commit was linked to by #11717 (closed)

stanhu 23 hours ago Still not quite sure the issue here. This sounds like the button to regenerate the key got dropped, and nobody noticed/cared?

mkozono 23 hours ago Hmm. Yeah it does seem like that. Confusingly, the screenshots show the button still there. When is that feature needed? Only to rotate the key regularly or if it may be compromised?

stanhu 23 hours ago I think so. I think I used it long ago to test the key generation worked

mkozono 23 hours ago Since it was removed during a feature change, I would suggest to remove the file and open an issue to track adding back this feature. It can attract comments and be marked related to the above issue. Though I suppose it's a low priority since it wasn't really missed.

It appears the "Regenerate SSH key" button for repo mirrors was removed during !10355 (merged). Should it be added back?

I'm labeling this typefeature because it wasn't noticed for so long, and since it was removed during a feature change, it won't be a simple revert.