### Godot version

4.1.dev (dc625bcbfc5b587ba8867481ee7a1f6a567c25d0)

### System information

Mageia 9, Linux

### Issue description

When importing a project in current `master`, the following error is raised for each asset that gets imported:
```
Attempting to parent and popup a dialog that already has a parent.
```

It seems to be raised once per asset, caused by the progress dialog.

CC @bruvzg

### Steps to reproduce

- Import a new project in Godot that contains importable assets, e.g. https://github.com/RPicster/godot4-demo-desert-light

### Minimal reproduction project

See above.
if (is_embedded()) {
		for (Window *parent_window : visible_parents) {
			parent_window->disconnect("focus_entered", callable_mp(this, &Popup::_parent_focused));
			parent_window->disconnect("tree_exited", callable_mp(this, &Popup::_deinitialize_visible_parents));
		}
		visible_parents.clear();
	}
}
void Popup::_update_theme_item_cache() {
	Window::_update_theme_item_cache();
	theme_cache.panel_style = get_theme_stylebox(SNAME("panel"));
}
void Popup::_notification(int p_what) {
	switch (p_what) {
		case NOTIFICATION_VISIBILITY_CHANGED: {
			if (!is_in_edited_scene_root()) {
				if (is_visible()) {
					_initialize_visible_parents();
				} else {
					_deinitialize_visible_parents();
					emit_signal(SNAME("popup_hide"));
					popped_up = false;
				}
			}
		} break;