### 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
for (TreeItem *current = root; current; current = current->get_next_visible()) {
		for (int i = 0; i < columns.size(); i++) {
			if (current->get_text(i) == p_find) {
				return current;
			}
		}
	}
	return nullptr;
}
TreeItem *Tree::get_item_with_metadata(const Variant &p_find, int p_column) const {
	if (p_column < 0) {
		for (TreeItem *current = root; current; current = current->get_next_in_tree()) {
			for (int i = 0; i < columns.size(); i++) {
				if (current->get_metadata(i) == p_find) {
					return current;
				}
			}
		}
		return nullptr;
	}
	for (TreeItem *current = root; current; current = current->get_next_in_tree()) {
		if (current->get_metadata(p_column) == p_find) {
			return current;
		}
	}
	return nullptr;
}
void Tree::_do_incr_search(const String &p_add) {