### 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?)
return play_position_pos;
}
void AnimationTimelineEdit::update_play_position() {
	play_position->queue_redraw();
}
void AnimationTimelineEdit::update_values() {
	if (!animation.is_valid() || editing) {
		return;
	}
	editing = true;
	if (use_fps && animation->get_step() > 0) {
		length->set_value(animation->get_length() / animation->get_step());
		length->set_step(1);
		length->set_tooltip_text(TTR("Animation length (frames)"));
		time_icon->set_tooltip_text(TTR("Animation length (frames)"));
		if (track_edit) {
			track_edit->editor->_update_key_edit();
		}
	} else {
		length->set_value(animation->get_length());
		length->set_step(0.0001);
		length->set_tooltip_text(TTR("Animation length (seconds)"));
		time_icon->set_tooltip_text(TTR("Animation length (seconds)"));
	}
	switch (animation->get_loop_mode()) {
		case Animation::LOOP_NONE: {
			loop->set_icon(get_theme_icon(SNAME("Loop"), SNAME("EditorIcons")));
			loop->set_pressed(false);
		} break;