### 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.
ClassDB::bind_method("_add_task", &BackgroundProgress::_add_task);
	ClassDB::bind_method("_task_step", &BackgroundProgress::_task_step);
	ClassDB::bind_method("_end_task", &BackgroundProgress::_end_task);
	ClassDB::bind_method("_update", &BackgroundProgress::_update);
}
void BackgroundProgress::add_task(const String &p_task, const String &p_label, int p_steps) {
	MessageQueue::get_singleton()->push_call(this, "_add_task", p_task, p_label, p_steps);
}
void BackgroundProgress::task_step(const String &p_task, int p_step) {
	
	bool no_updates = true;
	{
		_THREAD_SAFE_METHOD_
		no_updates = updates.is_empty();
	}
	if (no_updates) {
		MessageQueue::get_singleton()->push_call(this, "_update");
	}
	{
		_THREAD_SAFE_METHOD_
		updates[p_task] = p_step;
	}
}
void BackgroundProgress::end_task(const String &p_task) {