sync with official fork v1.7.0

This commit implements issue Raathigesh#186. I can't know if there is a snapshot
for each but I can add a button to the summary that opens the snapshot
for the file in the code editor. That's what this commit does. It adds
the button to the UI and a mutation to send to the server to open the
snapshot in the editor.
And it implements issue Raathigesh#191. There was already a button for generating
a snapshot, but it was only visible when there was a detected snapshot
error. This caused us to have to run known failing tests before we could
get the button to generate the snapshots. Now the button is there all
the time, so if you know your snapshots are out of date, then you can
generate them immediately and save time.