### 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
if (select_mode == SELECT_SINGLE && selected_item == p_item && selected_col == p_column) {
		selected_item = nullptr;
		selected_col = -1;
	} else {
		if (select_mode == SELECT_ROW && selected_item == p_item) {
			selected_item = nullptr;
			selected_col = -1;
		} else {
			if (select_mode == SELECT_MULTI) {
				selected_item = p_item;
				selected_col = p_column;
			}
		}
	}
	if (select_mode == SELECT_MULTI || select_mode == SELECT_SINGLE) {
		p_item->cells.write[p_column].selected = false;
	} else if (select_mode == SELECT_ROW) {
		for (int i = 0; i < p_item->cells.size(); i++) {
			p_item->cells.write[i].selected = false;
		}
	}
	queue_redraw();
}
void Tree::set_select_mode(SelectMode p_mode) {