Remove EditorFileDialog warning when skipping project directories

[akien-mga]

We might need better UX to handle this in EditorFileDialog, showing the directories as greyed out with a tooltip, but for now this silences a warning that users have no control over.

Removes this kind of warning that happens frequently when exporting projects and browsing to find where to export them:

WARNING: Detected another project.godot at /home/akien/tmp/godot/bug/Translation Example. The folder will be ignored.
     at: _should_skip_directory (editor/editor_file_system.cpp:2371)

[KoBeWi]

This reopens #77050

I think a better solution would be avoiding the warning in EditorFileDialog. It should only appear on the initial scan while the project is being opened.

[akien-mga]

I think warning if you have a project.godot in a subfolder of your edited project's folder is fair. That's not a supported use case and that's something you should fix.

But warning because you're browsing your filesystem outside the project's folder and happen to have other Godot projects somewhere is really annoying.

[KoBeWi]

if (EditorFileSystem::get_singleton()->first_scan) {
	WARN_PRINT_ONCE(vformat("Detected another project.godot at %s. The folder will be ignored.", p_path));
}