Reimport file when .import changes

[KoBeWi]

Fixes #60730

Editor was already detecting that .import file has changed, but _test_for_reimport() which triggers the actual reimport did not check that.

Might need some testing.

[turbohz]

@KoBeWi , thanks for looking into this!

I was unaware of your attempt, and created https://github.com/godotengine/godot/pull/85067 (for 3.x).

The approaches are certainly different: here the fix is about the modification time of files.

Mine is more potentially disruptive (modifies the format of the .md5 files in the .import folder), but seems to work, too.

There's also the possibility that the fixes need to be different for each major version, due to different root causes.

[akien-mga]

As we're reworking FS import stuff with #92303, might be worth including this too. I'd suggest waiting for #92303 to be merge, then rebase and make sure it works and we can include it too.

[akien-mga]

As we're reworking FS import stuff with #92303, might be worth including this too. I'd suggest waiting for #92303 to be merge, then rebase and make sure it works and we can include it too.

Can be rebased and re-tested now.

[KoBeWi]

Rebased and still works.

[akien-mga]

Thanks!