### 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.
ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_INDEX(p_flag, FLAG_MAX);
	flags[p_flag] = p_enabled;
	if (embedder) {
		embedder->_sub_window_update(this);
	} else if (window_id != DisplayServer::INVALID_WINDOW_ID) {
		if (!is_in_edited_scene_root()) {
			DisplayServer::get_singleton()->window_set_flag(DisplayServer::WindowFlags(p_flag), p_enabled, window_id);
		}
	}
}
bool Window::get_flag(Flags p_flag) const {
	ERR_READ_THREAD_GUARD_V(false);
	ERR_FAIL_INDEX_V(p_flag, FLAG_MAX, false);
	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
		if (!is_in_edited_scene_root()) {
			flags[p_flag] = DisplayServer::get_singleton()->window_get_flag(DisplayServer::WindowFlags(p_flag), window_id);
		}
	}
	return flags[p_flag];
}
bool Window::is_maximize_allowed() const {
	ERR_READ_THREAD_GUARD_V(false);
	if (window_id != DisplayServer::INVALID_WINDOW_ID) {
		return DisplayServer::get_singleton()->window_is_maximize_allowed(window_id);
	}
	return true;
}
void Window::request_attention() {