### 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
undo_redo->add_undo_method(animation.ptr(), "track_set_key_value", track, key, prev);
				undo_redo->add_do_method(this, "_update_obj", animation);
				undo_redo->add_undo_method(this, "_update_obj", animation);
				undo_redo->commit_action();
				setting = false;
				return true;
			}
		} break;
		case Animation::TYPE_METHOD: {
			Dictionary d_old = animation->track_get_key_value(track, key);
			Dictionary d_new = d_old.duplicate();
			bool change_notify_deserved = false;
			bool mergeable = false;
			if (name == "name") {
				d_new["method"] = p_value;
			} else if (name == "arg_count") {
				Vector<Variant> args = d_old["args"];
				args.resize(p_value);
				d_new["args"] = args;
				change_notify_deserved = true;
			} else if (name.begins_with("args/")) {
				Vector<Variant> args = d_old["args"];
				int idx = name.get_slice("/", 1).to_int();
				ERR_FAIL_INDEX_V(idx, args.size(), false);
				String what = name.get_slice("/", 2);
				if (what == "type") {
					Variant::Type t = Variant::Type(int(p_value));
					if (t != args[idx].get_type()) {
						Callable::CallError err;
						if (Variant::can_convert_strict(args[idx].get_type(), t)) {