### 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
step->set_max(1000000);
	step->set_step(0.0001);
	step->set_hide_slider(true);
	step->set_custom_minimum_size(Size2(100, 0) * EDSCALE);
	step->set_tooltip_text(TTR("Animation step value."));
	bottom_hb->add_child(step);
	step->connect("value_changed", callable_mp(this, &AnimationTrackEditor::_update_step));
	step->set_read_only(true);
	snap_mode = memnew(OptionButton);
	snap_mode->add_item(TTR("Seconds"));
	snap_mode->add_item(TTR("FPS"));
	bottom_hb->add_child(snap_mode);
	snap_mode->connect("item_selected", callable_mp(this, &AnimationTrackEditor::_snap_mode_changed));
	snap_mode->set_disabled(true);
	bottom_hb->add_child(memnew(VSeparator));
	zoom_icon = memnew(TextureRect);
	zoom_icon->set_v_size_flags(SIZE_SHRINK_CENTER);
	bottom_hb->add_child(zoom_icon);
	zoom = memnew(HSlider);
	zoom->set_step(0.01);
	zoom->set_min(0.0);
	zoom->set_max(2.0);
	zoom->set_value(1.0);
	zoom->set_custom_minimum_size(Size2(200, 0) * EDSCALE);
	zoom->set_v_size_flags(SIZE_SHRINK_CENTER);
	bottom_hb->add_child(zoom);
	timeline->set_zoom(zoom);
	edit = memnew(MenuButton);
	edit->set_shortcut_context(this);
	edit->set_text(TTR("Edit"));