### 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_INDEX(p_column, cells.size());
	_cell_selected(p_column);
}
void TreeItem::deselect(int p_column) {
	ERR_FAIL_INDEX(p_column, cells.size());
	_cell_deselected(p_column);
}
void TreeItem::add_button(int p_column, const Ref<Texture2D> &p_button, int p_id, bool p_disabled, const String &p_tooltip) {
	ERR_FAIL_INDEX(p_column, cells.size());
	ERR_FAIL_COND(!p_button.is_valid());
	TreeItem::Cell::Button button;
	button.texture = p_button;
	if (p_id < 0) {
		p_id = cells[p_column].buttons.size();
	}
	button.id = p_id;
	button.disabled = p_disabled;
	button.tooltip = p_tooltip;
	cells.write[p_column].buttons.push_back(button);
	cells.write[p_column].cached_minimum_size_dirty = true;
	_changed_notify(p_column);
}
int TreeItem::get_button_count(int p_column) const {
	ERR_FAIL_INDEX_V(p_column, cells.size(), -1);
	return cells[p_column].buttons.size();
}
Ref<Texture2D> TreeItem::get_button(int p_column, int p_index) const {