### 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
tree->item_changed(p_cell, this);
}
void TreeItem::_changed_notify() {
	tree->item_changed(-1, this);
}
void TreeItem::_cell_selected(int p_cell) {
	tree->item_selected(p_cell, this);
}
void TreeItem::_cell_deselected(int p_cell) {
	tree->item_deselected(p_cell, this);
}
void TreeItem::_change_tree(Tree *p_tree) {
	if (p_tree == tree) {
		return;
	}
	TreeItem *c = first_child;
	while (c) {
		c->_change_tree(p_tree);
		c = c->next;
	}
	if (tree) {
		if (tree->root == this) {
			tree->root = nullptr;
		}