### 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 (!p_item->cells[i].editable) {
							break;
						}
						Ref<Texture2D> downarrow = theme_cache.select_arrow;
						int cell_width = item_rect.size.x - downarrow->get_width();
						if (rtl) {
							if (outline_size > 0 && font_outline_color.a > 0) {
								p_item->cells[i].text_buf->draw_outline(ci, text_pos + Vector2(cell_width - text_width, 0), outline_size, font_outline_color);
							}
							p_item->cells[i].text_buf->draw(ci, text_pos + Vector2(cell_width - text_width, 0), cell_color);
						} else {
							if (outline_size > 0 && font_outline_color.a > 0) {
								p_item->cells[i].text_buf->draw_outline(ci, text_pos, outline_size, font_outline_color);
							}
							p_item->cells[i].text_buf->draw(ci, text_pos, cell_color);
						}
						Point2i arrow_pos = item_rect.position;
						arrow_pos.x += item_rect.size.x - downarrow->get_width();
						arrow_pos.y += Math::floor(((item_rect.size.y - downarrow->get_height())) / 2.0);
						downarrow->draw(ci, arrow_pos);
					} else {
						Ref<Texture2D> updown = theme_cache.updown;
						int cell_width = item_rect.size.x - updown->get_width();
						if (rtl) {
							if (outline_size > 0 && font_outline_color.a > 0) {
								p_item->cells[i].text_buf->draw_outline(ci, text_pos + Vector2(cell_width - text_width, 0), outline_size, font_outline_color);
							}
							p_item->cells[i].text_buf->draw(ci, text_pos + Vector2(cell_width - text_width, 0), cell_color);
						} else {
							if (outline_size > 0 && font_outline_color.a > 0) {