### Godot version

4.0.dev (c309de53997feff3286295fb2d71657f112a15db)

### System information

Linux, Nvidia, Vulkan

### Issue description

Editor segfaults when certain conditions are met when using the AnimationPlayer editor.

### Steps to reproduce

1. Create multiple animations, saved into a animation collection
2. Open an existing animation, then make a new empty animation
3. Change from seconds to fps, or add a new property to animate ()
4. Editor crashes

NOTE: It is slightly random and I have not found a perfect repro

### Minimal reproduction project

N/A (TBD?)
int key = animation->track_find_key(track, key_ofs, Animation::FIND_MODE_APPROX);
	ERR_FAIL_COND_V(key == -1, false);
	String name = p_name;
	if (name == "easing") {
		float val = p_value;
		float prev_val = animation->track_get_key_transition(track, key);
		setting = true;
		EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
		undo_redo->create_action(TTR("Animation Change Transition"), UndoRedo::MERGE_ENDS);
		undo_redo->add_do_method(animation.ptr(), "track_set_key_transition", track, key, val);
		undo_redo->add_undo_method(animation.ptr(), "track_set_key_transition", track, key, prev_val);
		undo_redo->add_do_method(this, "_update_obj", animation);
		undo_redo->add_undo_method(this, "_update_obj", animation);
		undo_redo->commit_action();
		setting = false;
		return true;
	}
	EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
	switch (animation->track_get_type(track)) {
		case Animation::TYPE_POSITION_3D:
		case Animation::TYPE_ROTATION_3D:
		case Animation::TYPE_SCALE_3D: {
			if (name == "position" || name == "rotation" || name == "scale") {
				Variant old = animation->track_get_key_value(track, key);
				setting = true;
				String chan;
				switch (animation->track_get_type(track)) {
					case Animation::TYPE_POSITION_3D:
						chan = "Position3D";
						break;