### 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 (key_edit) {
		
		if (InspectorDock::get_inspector_singleton()->get_edited_object() == key_edit) {
			EditorNode::get_singleton()->push_item(nullptr);
		}
		
		memdelete(key_edit);
		key_edit = nullptr;
	}
	if (multi_key_edit) {
		if (InspectorDock::get_inspector_singleton()->get_edited_object() == multi_key_edit) {
			EditorNode::get_singleton()->push_item(nullptr);
		}
		memdelete(multi_key_edit);
		multi_key_edit = nullptr;
	}
}
void AnimationTrackEditor::_clear_selection(bool p_update) {
	selection.clear();
	if (p_update) {
		_redraw_tracks();
	}
	_clear_key_edit();
}
void AnimationTrackEditor::_update_key_edit() {