### Godot version

4.2 dev1

### 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

Calling `Tree.propagate_check()` after an item is unchecked does not properly uncheck the parents. They are left in partially checked state.

It's easy to observe in theme editor:

https://github.com/godotengine/godot/assets/2223172/71d0479c-0a5e-48d3-957f-d90379a95c22



### Steps to reproduce

1. Edit a Theme resource
2. Go to Manage Items... menu
3. Go to Import Items tab
4. Unfold something
5. Check and uncheck a child checkbox

### Minimal reproduction project

N/A
if (i == 0) {
				if (p_item->cells[0].selected && select_mode == SELECT_ROW) {
					const Rect2 content_rect = _get_content_rect();
					Rect2i row_rect = Rect2i(Point2i(content_rect.position.x, item_rect.position.y), Size2i(content_rect.size.x, item_rect.size.y));
					if (rtl) {
						row_rect.position.x = get_size().width - row_rect.position.x - row_rect.size.x;
					}
					if (has_focus()) {
						theme_cache.selected_focus->draw(ci, row_rect);
					} else {
						theme_cache.selected->draw(ci, row_rect);
					}
				}
			}
			if ((select_mode == SELECT_ROW && selected_item == p_item) || p_item->cells[i].selected || !p_item->has_meta("__focus_rect")) {
				Rect2i r = cell_rect;
				p_item->set_meta("__focus_rect", Rect2(r.position, r.size));
				if (select_mode != SELECT_ROW) {
					if (rtl) {
						r.position.x = get_size().width - r.position.x - r.size.x;
					}
					if (p_item->cells[i].selected) {
						if (has_focus()) {
							theme_cache.selected_focus->draw(ci, r);
						} else {
							theme_cache.selected->draw(ci, r);
						}
					}
				}
			}