Save conflict actions show up for any diff editor, not just one

[isidorn]

1. Make a save conflict on a local file on disk
2. Notice the nice actions in the editor title bar for helping you resolve the conflict
3. Resolve the conflict in some way. Notice that the actions in the title bar are still there and they are not going away
4. Reloading vscode finally removes them

[bpasero]

Looks like this was already happening in stable.

[bpasero]

I fixed the issue with actions showing up in all diff editors and merge this into #22275

To verify:

• get into a save conflict (make file dirty, make changes from other editor, try to save)
• click on "Resolve" to start seeing the diff editor with actions to resolve the save conflict
• verify the actions show up only for the diff editor of the save conflict but a) not for any other editor and b) not for other diff editors
• verify you can resolve the save conflict by either accepting or reverting (try both)