### 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 (selection.size() && animation.is_valid() && (!transpose || (_get_track_selected() >= 0 && _get_track_selected() < animation->get_track_count()))) {
		int top_track = 0x7FFFFFFF;
		float top_time = 1e10;
		for (RBMap<SelectedKey, KeyInfo>::Element *E = selection.back(); E; E = E->prev()) {
			const SelectedKey &sk = E->key();
			float t = animation->track_get_key_time(sk.track, sk.key);
			if (t < top_time) {
				top_time = t;
			}
			if (sk.track < top_track) {
				top_track = sk.track;
			}
		}
		ERR_FAIL_COND(top_track == 0x7FFFFFFF || top_time == 1e10);
		
		int start_track = transpose ? _get_track_selected() : top_track;
		EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
		undo_redo->create_action(TTR("Animation Duplicate Keys"));
		List<Pair<int, float>> new_selection_values;
		for (RBMap<SelectedKey, KeyInfo>::Element *E = selection.back(); E; E = E->prev()) {
			const SelectedKey &sk = E->key();
			float t = animation->track_get_key_time(sk.track, sk.key);
			float dst_time = t + (timeline->get_play_position() - top_time);
			int dst_track = sk.track + (start_track - top_track);
			if (dst_track < 0 || dst_track >= animation->get_track_count()) {
				continue;
			}