### 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?)
subindices.push_back(":y");
			subindices.push_back(":z");
		} break;
		case Variant::QUATERNION: {
			subindices.push_back(":x");
			subindices.push_back(":y");
			subindices.push_back(":z");
			subindices.push_back(":w");
		} break;
		case Variant::COLOR: {
			subindices.push_back(":r");
			subindices.push_back(":g");
			subindices.push_back(":b");
			subindices.push_back(":a");
		} break;
		case Variant::PLANE: {
			subindices.push_back(":x");
			subindices.push_back(":y");
			subindices.push_back(":z");
			subindices.push_back(":d");
		} break;
		default: {
			if (r_valid) {
				*r_valid = false;
			}
		}
	}
	return subindices;
}
AnimationTrackEditor::TrackIndices AnimationTrackEditor::_confirm_insert(InsertData p_id, TrackIndices p_next_tracks, bool p_reset_wanted, Ref<Animation> p_reset_anim, bool p_create_beziers) {