### 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
ERR_FAIL_COND_V(blocked > 0, nullptr);
	TreeItem *ti = nullptr;
	if (p_parent) {
		ERR_FAIL_COND_V_MSG(p_parent->tree != this, nullptr, "A different tree owns the given parent");
		ti = p_parent->create_child(p_index);
	} else {
		if (!root) {
			
			ti = memnew(TreeItem(this));
			ERR_FAIL_NULL_V(ti, nullptr);
			ti->cells.resize(columns.size());
			ti->is_root = true;
			root = ti;
		} else {
			
			ti = create_item(root, p_index);
		}
	}
	return ti;
}
TreeItem *Tree::get_root() const {