Ask before restarting project from settings

[KoBeWi]

Fixes #43302
If you have only scenes that can be saved automatically, the editor will save them and restart without asking like before.

[ryevdokimov]

Works, but note the error in the output tab after pressing Save & Restart. Not sure if it is relevant to this PR though.

2025-01-25.17-43-23.mp4

[KoBeWi]

The save confirm dialog can't properly appear over other dialogs. It's not directly related to this PR, but makes the fix bugged :/

[ryevdokimov]

Try it with this: #102070

[ryevdokimov]

The same thing should be done for project settings and possibly other places.

Any reason not to modify restart_editor() to just always do this? As it stands even the EditorInterface call is dangerous even with save: = true, since it will lead to lost progress.

[KoBeWi]

Makes sense, I changed restart_editor() instead.
Though the problem is that it allows to cancel restarting and some options don't support that properly, e.g. renderer change. I'd worry about that once someone runs into this issue though, as it's nothing major.

[ryevdokimov]

Works with: #102070

Tested in single and multi-window modes, and the various different scenarios. Code looks fine.

2025-01-28.11-19-12.mp4

[Calinou]

Tested locally, it works as expected (both from the project settings and editor settings).

Code looks good to me.

[akien-mga]

Thanks!