### 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?)
add_child(insert_confirm);
	insert_confirm->connect("confirmed", callable_mp(this, &AnimationTrackEditor::_confirm_insert_list));
	VBoxContainer *icvb = memnew(VBoxContainer);
	insert_confirm->add_child(icvb);
	insert_confirm_text = memnew(Label);
	icvb->add_child(insert_confirm_text);
	HBoxContainer *ichb = memnew(HBoxContainer);
	icvb->add_child(ichb);
	insert_confirm_bezier = memnew(CheckBox);
	insert_confirm_bezier->set_text(TTR("Use Bezier Curves"));
	insert_confirm_bezier->set_pressed(EDITOR_GET("editors/animation/default_create_bezier_tracks"));
	ichb->add_child(insert_confirm_bezier);
	insert_confirm_reset = memnew(CheckBox);
	insert_confirm_reset->set_text(TTR("Create RESET Track(s)", ""));
	insert_confirm_reset->set_pressed(EDITOR_GET("editors/animation/default_create_reset_tracks"));
	ichb->add_child(insert_confirm_reset);
	box_selection = memnew(Control);
	add_child(box_selection);
	box_selection->set_as_top_level(true);
	box_selection->set_mouse_filter(MOUSE_FILTER_IGNORE);
	box_selection->hide();
	box_selection->connect("draw", callable_mp(this, &AnimationTrackEditor::_box_selection_draw));
	
	Ref<AnimationTrackEditDefaultPlugin> def_plugin;
	def_plugin.instantiate();
	add_track_edit_plugin(def_plugin);
	
	optimize_dialog = memnew(ConfirmationDialog);
	add_child(optimize_dialog);
	optimize_dialog->set_title(TTR("Anim. Optimizer"));