### Godot version

4.0 beta 10

### System information

Windows 11 Vulkan

### Issue description

Looked through the issues list, but couldn't find something like this, sorry in advance if this has already been reported.

There is a few cases (in the pictures below) where list of Actions in Input Map may not always show a scrollbar even if the actions list overflows (I imagine this could also happen for the widget that Input Map uses).

![image](https://user-images.githubusercontent.com/39958198/210003566-cf60dbaf-921f-485b-b0a9-51ffc28d0244.png)

![New Bitmap image](https://user-images.githubusercontent.com/39958198/210004079-8eb2e6a1-0cf5-4a7c-8905-a4e3cfd0ec5d.png)

![image](https://user-images.githubusercontent.com/39958198/210004165-a6b6790b-248a-4f68-b4d0-b44b25afdf4f.png)

![image](https://user-images.githubusercontent.com/39958198/210004537-aca52194-a464-48b9-b818-24782706de45.png)


### Steps to reproduce

The pictures are clearer than anything I could write here: "a picture is worth 1000 words"

### Minimal reproduction project

N/A
if ((p_item == root && hide_root) || !p_item->is_visible()) {
		return 0;
	}
	ERR_FAIL_COND_V(theme_cache.font.is_null(), 0);
	int height = 0;
	for (int i = 0; i < columns.size(); i++) {
		if (p_item->cells[i].dirty) {
			const_cast<Tree *>(this)->update_item_cell(p_item, i);
		}
		height = MAX(height, p_item->cells[i].text_buf->get_size().y);
		for (int j = 0; j < p_item->cells[i].buttons.size(); j++) {
			Size2i s; 
			s += p_item->cells[i].buttons[j].texture->get_size();
			if (s.height > height) {
				height = s.height;
			}
		}
		switch (p_item->cells[i].mode) {
			case TreeItem::CELL_MODE_CHECK: {
				int check_icon_h = theme_cache.checked->get_height();
				if (height < check_icon_h) {
					height = check_icon_h;
				}
				[[fallthrough]];