### 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
c.selected = false;
				}
			}
		} else if (select_mode == SELECT_SINGLE || select_mode == SELECT_MULTI) {
			if (!r_in_range && &selected_cell == &c) {
				if (!selected_cell.selected || allow_reselect) {
					selected_cell.selected = true;
					selected_item = p_selected;
					selected_col = i;
					emit_signal(SNAME("cell_selected"));
					if (select_mode == SELECT_MULTI) {
						emit_signal(SNAME("multi_selected"), p_current, i, true);
					} else if (select_mode == SELECT_SINGLE) {
						emit_signal(SNAME("item_selected"));
					}
				} else if (select_mode == SELECT_MULTI && (selected_item != p_selected || selected_col != i)) {
					selected_item = p_selected;
					selected_col = i;
					emit_signal(SNAME("cell_selected"));
				}
			} else {
				if (r_in_range && *r_in_range && !p_force_deselect) {
					if (!c.selected && c.selectable) {
						c.selected = true;
						emit_signal(SNAME("multi_selected"), p_current, i, true);
					}
				} else if (!r_in_range || p_force_deselect) {
					if (select_mode == SELECT_MULTI && c.selected) {
						emit_signal(SNAME("multi_selected"), p_current, i, false);
					}