### 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
emit_signal(SNAME("multi_selected"), p_item, col, false);
					} else {
						p_item->select(col);
						emit_signal(SNAME("multi_selected"), p_item, col, true);
						emit_signal(SNAME("item_mouse_selected"), get_local_mouse_position(), p_button);
					}
				} else {
					if (select_mode == SELECT_MULTI && p_mod->is_shift_pressed() && selected_item && selected_item != p_item) {
						bool inrange = false;
						select_single_item(p_item, root, col, selected_item, &inrange);
						emit_signal(SNAME("item_mouse_selected"), get_local_mouse_position(), p_button);
					} else {
						int icount = _count_selected_items(root);
						if (select_mode == SELECT_MULTI && icount > 1 && p_button != MouseButton::RIGHT) {
							single_select_defer = p_item;
							single_select_defer_column = col;
						} else {
							if (p_button != MouseButton::RIGHT || !c.selected) {
								select_single_item(p_item, root, col);
							}
							emit_signal(SNAME("item_mouse_selected"), get_local_mouse_position(), p_button);
						}
					}
					queue_redraw();
				}
			}
		}
		if (!c.editable) {
			return -1; 
		}