Comment the Actions run link on `!build` requests from Core Team for easier troubleshooting

[bluelinden]

All this does is immediately post a comment with the Actions build link when the core team triggers a build. It then edits that comment when the build finishes.

It means I don't need to go looking through the Actions tab for my build in case it fails.

Just a little development QoL patch!

[TrueDoctor]

!build

[github-actions[bot]]

📦 Build Complete for 9f713d4b3db1a6d277d651ddfb151b6df568a230
https://eeb8b335.graphite.pages.dev

[bluelinden]

!build

this actions run won't build using the new workflow - i believe Keavon said earlier that it has to be on the default branch.