### 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?)
Variant old = args[idx];
							Variant *ptrs[1] = { &old };
							Variant::construct(t, args.write[idx], (const Variant **)ptrs, 1, err);
						} else {
							Variant::construct(t, args.write[idx], nullptr, 0, err);
						}
						change_notify_deserved = true;
						d_new["args"] = args;
					}
				} else if (what == "value") {
					Variant value = p_value;
					if (value.get_type() == Variant::NODE_PATH) {
						_fix_node_path(value);
					}
					args.write[idx] = value;
					d_new["args"] = args;
					mergeable = true;
				}
			}
			if (mergeable) {
				undo_redo->create_action(TTR("Animation Change Call"), UndoRedo::MERGE_ENDS);
			} else {
				undo_redo->create_action(TTR("Animation Change Call"));
			}
			setting = true;
			undo_redo->add_do_method(animation.ptr(), "track_set_key_value", track, key, d_new);
			undo_redo->add_undo_method(animation.ptr(), "track_set_key_value", track, key, d_old);
			undo_redo->add_do_method(this, "_update_obj", animation);
			undo_redo->add_undo_method(this, "_update_obj", animation);
			undo_redo->commit_action();