### Godot version

4.2 dev3

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

If you have a Method Track with multiple calls to the same method, they are joined together and makes things unreadable:
![image](https://github.com/godotengine/godot/assets/2223172/a2ab8446-28a1-440b-b0d5-5049f5d705b4)
The horizontal line shouldn't be used here. I think it might be a regression.

### Steps to reproduce

1. Add AnimationPlayer
2. Add a Method Track (with Add Track button)
3. Add some key to the track
4. Add another key with the same method

### Minimal reproduction project

N/A
}
				if (!track_type.is_empty()) {
					text += vformat(" (%s)", track_type);
				}
				TreeItem *it = track_copy_select->create_item(troot);
				it->set_editable(0, true);
				it->set_selectable(0, true);
				it->set_cell_mode(0, TreeItem::CELL_MODE_CHECK);
				it->set_icon(0, icon);
				it->set_text(0, text);
				Dictionary md;
				md["track_idx"] = i;
				md["path"] = path;
				it->set_metadata(0, md);
			}
			track_copy_dialog->popup_centered(Size2(350, 500) * EDSCALE);
		} break;
		case EDIT_COPY_TRACKS_CONFIRM: {
			track_clipboard.clear();
			TreeItem *tree_root = track_copy_select->get_root();
			if (tree_root) {
				TreeItem *it = tree_root->get_first_child();
				while (it) {
					Dictionary md = it->get_metadata(0);
					int idx = md["track_idx"];
					if (it->is_checked(0) && idx >= 0 && idx < animation->get_track_count()) {
						TrackClipboard tc;
						tc.base_path = animation->track_get_path(idx);
						tc.full_path = md["path"];
						tc.track_type = animation->track_get_type(idx);