### 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
TreeItem *ti = memnew(TreeItem(tree));
	if (tree) {
		ti->cells.resize(tree->columns.size());
		tree->queue_redraw();
	}
	TreeItem *item_prev = nullptr;
	TreeItem *item_next = first_child;
	int idx = 0;
	while (item_next) {
		if (idx == p_index) {
			item_next->prev = ti;
			ti->next = item_next;
			break;
		}
		item_prev = item_next;
		item_next = item_next->next;
		idx++;
	}
	if (item_prev) {
		item_prev->next = ti;
		ti->prev = item_prev;
		if (!children_cache.is_empty()) {
			if (ti->next) {
				children_cache.insert(p_index, ti);
			} else {
				children_cache.append(ti);
			}
		}
	} else {