### Godot version

4.0.rc

### System information

Any

### Issue description

If the RESET animation is generated at the same time as the Bezier track is generated, the bezier edit button will not be active.

![image](https://user-images.githubusercontent.com/61938263/218256176-88b1b196-7b6b-4404-84ad-e8694f23bb1b.png)

Also, if you delete a track in the Bezier Editor, or in undo redo, it will not update correctly.

### Steps to reproduce

![image](https://user-images.githubusercontent.com/61938263/218256230-4b0219d5-87e4-453a-8294-59f8feb0cfd5.png)


### Minimal reproduction project

N/A
EditorNode::get_singleton()->show_warning(
			TTR("This animation belongs to an imported scene, so changes to imported tracks will not be saved.\n\nTo modify this animation, navigate to the scene's Advanced Import settings and select the animation.\nSome options, including looping, are available here. To add custom tracks, enable \"Save To File\" and\n\"Keep Custom Tracks\"."),
			TTR("Warning: Editing imported animation"));
}
void AnimationTrackEditor::_select_all_tracks_for_copy() {
	TreeItem *track = track_copy_select->get_root()->get_first_child();
	if (!track) {
		return;
	}
	bool all_selected = true;
	while (track) {
		if (!track->is_checked(0)) {
			all_selected = false;
		}
		track = track->get_next();
	}
	track = track_copy_select->get_root()->get_first_child();
	while (track) {
		track->set_checked(0, !all_selected);
		track = track->get_next();
	}
}
void AnimationTrackEditor::_bind_methods() {