### 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
return parent;
}
TreeItem *TreeItem::get_first_child() const {
	return first_child;
}
TreeItem *TreeItem::_get_prev_in_tree(bool p_wrap, bool p_include_invisible) {
	TreeItem *current = this;
	TreeItem *prev_item = current->get_prev();
	if (!prev_item) {
		current = current->parent;
		if (current == tree->root && tree->hide_root) {
			return nullptr;
		} else if (!current) {
			if (p_wrap) {
				current = this;
				TreeItem *temp = this->get_next_visible();
				while (temp) {
					current = temp;
					temp = temp->get_next_visible();
				}