### 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?)
time_icon = memnew(TextureRect);
	time_icon->set_v_size_flags(SIZE_SHRINK_CENTER);
	time_icon->set_tooltip_text(TTR("Animation length (seconds)"));
	len_hb->add_child(time_icon);
	length = memnew(EditorSpinSlider);
	length->set_min(0.0001);
	length->set_max(36000);
	length->set_step(0.0001);
	length->set_allow_greater(true);
	length->set_custom_minimum_size(Vector2(70 * EDSCALE, 0));
	length->set_hide_slider(true);
	length->set_tooltip_text(TTR("Animation length (seconds)"));
	length->connect("value_changed", callable_mp(this, &AnimationTimelineEdit::_anim_length_changed));
	len_hb->add_child(length);
	loop = memnew(Button);
	loop->set_flat(true);
	loop->set_tooltip_text(TTR("Animation Looping"));
	loop->connect("pressed", callable_mp(this, &AnimationTimelineEdit::_anim_loop_pressed));
	loop->set_toggle_mode(true);
	len_hb->add_child(loop);
	add_child(len_hb);
	add_track->hide();
	add_track->get_popup()->connect("index_pressed", callable_mp(this, &AnimationTimelineEdit::_track_added));
	len_hb->hide();
	panner.instantiate();
	panner->set_callbacks(callable_mp(this, &AnimationTimelineEdit::_pan_callback), callable_mp(this, &AnimationTimelineEdit::_zoom_callback));
	panner->set_pan_axis(ViewPanner::PAN_AXIS_HORIZONTAL);
	set_layout_direction(Control::LAYOUT_DIRECTION_LTR);
}
void AnimationTrackEdit::_notification(int p_what) {