### Godot version

4.x (beta 5, 6, 7, 8, 9, 10) didn't tested versions before beta 5
Also reproducable in current master: c5bfe13
  
### System information

Windows 10

### Issue description

When clicking around the bottom edge of the scrollbar grabber, it is not detected as such and instead jumps to a lower position, as if you click on the free area of the scrollbar.

The red marked area is not detected as grabber click. Everything is fine on the top edge.
![image](https://user-images.githubusercontent.com/66004280/210325316-6718b793-b3ec-4c3a-b2b3-0df0f431a222.png)

### Steps to reproduce

Just use a `ScrollContainer` with e.g. a `VBox` and many `Button`s.

See the video:

https://user-images.githubusercontent.com/66004280/210325006-718e0f57-49b3-4aa1-ad35-653b9c66d9fa.mp4

### Minimal reproduction project

N/A
Ref<StyleBox> style(memnew(StyleBoxEmpty));
	style->set_default_margin_individual(p_margin_left * scale, p_margin_top * scale, p_margin_right * scale, p_margin_bottom * scale);
	return style;
}
void fill_default_theme(Ref<Theme> &theme, const Ref<Font> &default_font, const Ref<Font> &bold_font, const Ref<Font> &bold_italics_font, const Ref<Font> &italics_font, Ref<Texture2D> &default_icon, Ref<StyleBox> &default_style, float p_scale) {
	scale = p_scale;
	
	theme->set_default_font(default_font);
	theme->set_default_font_size(default_font_size * scale);
	theme->set_default_base_scale(scale);
	
	const Color control_font_color = Color(0.875, 0.875, 0.875);
	const Color control_font_low_color = Color(0.7, 0.7, 0.7);
	const Color control_font_lower_color = Color(0.65, 0.65, 0.65);
	const Color control_font_hover_color = Color(0.95, 0.95, 0.95);
	const Color control_font_focus_color = Color(0.95, 0.95, 0.95);
	const Color control_font_disabled_color = control_font_color * Color(1, 1, 1, 0.5);
	const Color control_font_placeholder_color = Color(control_font_color.r, control_font_color.g, control_font_color.b, 0.6f);
	const Color control_font_pressed_color = Color(1, 1, 1);
	const Color control_selection_color = Color(0.5, 0.5, 0.5);
	
	const Color style_normal_color = Color(0.1, 0.1, 0.1, 0.6);
	const Color style_hover_color = Color(0.225, 0.225, 0.225, 0.6);