### 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_V(p_column, cells.size(), Ref<Texture2D>());
	ERR_FAIL_INDEX_V(p_index, cells[p_column].buttons.size(), Ref<Texture2D>());
	return cells[p_column].buttons[p_index].texture;
}
String TreeItem::get_button_tooltip_text(int p_column, int p_index) const {
	ERR_FAIL_INDEX_V(p_column, cells.size(), String());
	ERR_FAIL_INDEX_V(p_index, cells[p_column].buttons.size(), String());
	return cells[p_column].buttons[p_index].tooltip;
}
int TreeItem::get_button_id(int p_column, int p_index) const {
	ERR_FAIL_INDEX_V(p_column, cells.size(), -1);
	ERR_FAIL_INDEX_V(p_index, cells[p_column].buttons.size(), -1);
	return cells[p_column].buttons[p_index].id;
}
void TreeItem::erase_button(int p_column, int p_index) {
	ERR_FAIL_INDEX(p_column, cells.size());
	ERR_FAIL_INDEX(p_index, cells[p_column].buttons.size());
	cells.write[p_column].buttons.remove_at(p_index);
	_changed_notify(p_column);
}
int TreeItem::get_button_by_id(int p_column, int p_id) const {
	ERR_FAIL_INDEX_V(p_column, cells.size(), -1);
	for (int i = 0; i < cells[p_column].buttons.size(); i++) {
		if (cells[p_column].buttons[i].id == p_id) {
			return i;
		}
	}
	return -1;
}
void TreeItem::set_button_tooltip_text(int p_column, int p_index, const String &p_tooltip) {