fix(ci): don't allow empty commits in update generated files task; skip task when previous commit was also generated by it

[gribnoysup]

This re-enables the update generated task with some safeguards added to make sure that hopefully never start spamming those automatic commits again, in particular:

• Check that the previous commit was not autogenerated by the same task by checking the title (these runs are still allowed for the cron job)
• Format autogenerated files before commiting them. This should make sure that empty commits don't happen
• Check that commit is not empty before pushing it back to main. Seems like the way precommit hooks interact with git empty commit check allows empty commit to happen even if the flag enabling them is not passed. I'm changing the logic here allowing empty commits and explicitly checking that it's not empty before pushing, this should make sure that even if we change the precommit in the future and we start once again generating empty commits by accident, this task would always be able to skip pushes in those cases