### 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?)
if (pos.x >= timeline->get_name_limit() && pos.x <= get_size().width - timeline->get_buttons_width()) {
			
			float offset = (pos.x - timeline->get_name_limit()) / timeline->get_zoom_scale();
			if (!read_only) {
				if (!menu) {
					menu = memnew(PopupMenu);
					add_child(menu);
					menu->connect("id_pressed", callable_mp(this, &AnimationTrackEdit::_menu_selected));
				}
				menu->clear();
				menu->add_icon_item(get_theme_icon(SNAME("Key"), SNAME("EditorIcons")), TTR("Insert Key"), MENU_KEY_INSERT);
				if (editor->is_selection_active()) {
					menu->add_separator();
					menu->add_icon_item(get_theme_icon(SNAME("Duplicate"), SNAME("EditorIcons")), TTR("Duplicate Key(s)"), MENU_KEY_DUPLICATE);
					AnimationPlayer *player = AnimationPlayerEditor::get_singleton()->get_player();
					if (!player->has_animation(SceneStringNames::get_singleton()->RESET) || animation != player->get_animation(SceneStringNames::get_singleton()->RESET)) {
						menu->add_icon_item(get_theme_icon(SNAME("Reload"), SNAME("EditorIcons")), TTR("Add RESET Value(s)"), MENU_KEY_ADD_RESET);
					}
					menu->add_separator();
					menu->add_icon_item(get_theme_icon(SNAME("Remove"), SNAME("EditorIcons")), TTR("Delete Key(s)"), MENU_KEY_DELETE);
				}
				menu->reset_size();
				menu->set_position(get_screen_position() + get_local_mouse_position());
				menu->popup();
				insert_at_pos = offset + timeline->get_value();
				accept_event();
			}
		}
	}
	if (mb.is_valid() && !mb->is_pressed() && mb->get_button_index() == MouseButton::LEFT && clicking_on_name) {