### 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?)
to_v = a + fmod(2.0 * to_diff, Math_TAU) - to_diff;
						}
						Variant delta_v = Animation::subtract_variant(to_v, from_v);
						double duration = to_t - from_t;
						double fixed_duration = duration - UNIT_EPSILON; 
						for (double delta_t = dur_step; delta_t < fixed_duration; delta_t += dur_step) {
							Pair<real_t, Variant> keydata;
							keydata.first = from_t + delta_t;
							keydata.second = Tween::interpolate_variant(from_v, delta_v, delta_t, duration, transition_type, ease_type);
							insert_queue_new.append(keydata);
						}
					}
				}
				
				for (int i = 0; i < insert_queue_new.size(); i++) {
					undo_redo->add_do_method(animation.ptr(), "track_insert_key", track, insert_queue_new[i].first, insert_queue_new[i].second);
					undo_redo->add_undo_method(animation.ptr(), "track_remove_key_at_time", track, insert_queue_new[i].first);
				}
				++E;
			}
			undo_redo->add_do_method(this, "_clear_selection_for_anim", animation);
			undo_redo->add_undo_method(this, "_clear_selection_for_anim", animation);
			undo_redo->add_do_method(this, "_redraw_tracks");
			undo_redo->add_undo_method(this, "_redraw_tracks");
			undo_redo->commit_action();
			_update_key_edit();
		} break;
		case EDIT_DUPLICATE_SELECTION: {
			if (bezier_edit->is_visible()) {
				bezier_edit->duplicate_selection();