### 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
dynamic_font.instantiate();
		dynamic_font->set_data_ptr(_font_OpenSans_SemiBold, _font_OpenSans_SemiBold_size);
		dynamic_font->set_subpixel_positioning(p_font_subpixel);
		dynamic_font->set_hinting(p_font_hinting);
		dynamic_font->set_antialiasing(p_font_antialiasing);
		dynamic_font->set_multichannel_signed_distance_field(p_font_msdf);
		dynamic_font->set_generate_mipmaps(p_font_generate_mipmaps);
		default_font = dynamic_font;
	}
	if (default_font.is_valid()) {
		bold_font.instantiate();
		bold_font->set_base_font(default_font);
		bold_font->set_variation_embolden(1.2);
		bold_italics_font.instantiate();
		bold_italics_font->set_base_font(default_font);
		bold_italics_font->set_variation_embolden(1.2);
		bold_italics_font->set_variation_transform(Transform2D(1.0, 0.2, 0.0, 1.0, 0.0, 0.0));
		italics_font.instantiate();
		italics_font->set_base_font(default_font);
		italics_font->set_variation_transform(Transform2D(1.0, 0.2, 0.0, 1.0, 0.0, 0.0));
	}
	fill_default_theme(t, default_font, bold_font, bold_italics_font, italics_font, default_icon, default_style, default_scale);
	ThemeDB::get_singleton()->set_default_theme(t);
	ThemeDB::get_singleton()->set_fallback_base_scale(default_scale);
	ThemeDB::get_singleton()->set_fallback_icon(default_icon);
	ThemeDB::get_singleton()->set_fallback_stylebox(default_style);
	ThemeDB::get_singleton()->set_fallback_font(default_font);
	ThemeDB::get_singleton()->set_fallback_font_size(default_font_size * default_scale);
}