### 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?)
bake_label2->set_text("Blendshape Track:");
	bake_label3->set_text("Value Track:");
	bake_label4->set_text("FPS:");
	bake_grid->add_child(bake_label1);
	bake_grid->add_child(bake_trs);
	bake_grid->add_child(bake_label2);
	bake_grid->add_child(bake_blendshape);
	bake_grid->add_child(bake_label3);
	bake_grid->add_child(bake_value);
	bake_grid->add_child(bake_label4);
	bake_grid->add_child(bake_fps);
	
	track_copy_dialog = memnew(ConfirmationDialog);
	add_child(track_copy_dialog);
	track_copy_dialog->set_title(TTR("Select Tracks to Copy"));
	track_copy_dialog->set_ok_button_text(TTR("Copy"));
	VBoxContainer *track_copy_vbox = memnew(VBoxContainer);
	track_copy_dialog->add_child(track_copy_vbox);
	Button *select_all_button = memnew(Button);
	select_all_button->set_text(TTR("Select All/None"));
	select_all_button->connect("pressed", callable_mp(this, &AnimationTrackEditor::_select_all_tracks_for_copy));
	track_copy_vbox->add_child(select_all_button);
	track_copy_select = memnew(Tree);
	track_copy_select->set_h_size_flags(SIZE_EXPAND_FILL);
	track_copy_select->set_v_size_flags(SIZE_EXPAND_FILL);
	track_copy_select->set_hide_root(true);
	track_copy_vbox->add_child(track_copy_select);
	track_copy_dialog->connect("confirmed", callable_mp(this, &AnimationTrackEditor::_edit_menu_pressed).bind(EDIT_COPY_TRACKS_CONFIRM));
}
AnimationTrackEditor::~AnimationTrackEditor() {