### 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
style_line_edit_read_only->set_border_width(SIDE_BOTTOM, 2);
	style_line_edit_read_only->set_border_color(style_pressed_color * Color(1, 1, 1, 0.5));
	theme->set_stylebox("read_only", "LineEdit", style_line_edit_read_only);
	theme->set_font("font", "LineEdit", Ref<Font>());
	theme->set_font_size("font_size", "LineEdit", -1);
	theme->set_color("font_color", "LineEdit", control_font_color);
	theme->set_color("font_selected_color", "LineEdit", control_font_pressed_color);
	theme->set_color("font_uneditable_color", "LineEdit", control_font_disabled_color);
	theme->set_color("font_placeholder_color", "LineEdit", control_font_placeholder_color);
	theme->set_color("font_outline_color", "LineEdit", Color(1, 1, 1));
	theme->set_color("caret_color", "LineEdit", control_font_hover_color);
	theme->set_color("selection_color", "LineEdit", control_selection_color);
	theme->set_color("clear_button_color", "LineEdit", control_font_color);
	theme->set_color("clear_button_color_pressed", "LineEdit", control_font_pressed_color);
	theme->set_constant("minimum_character_width", "LineEdit", 4);
	theme->set_constant("outline_size", "LineEdit", 0);
	theme->set_constant("caret_width", "LineEdit", 1);
	theme->set_icon("clear", "LineEdit", icons["line_edit_clear"]);
	
	theme->set_stylebox("background", "ProgressBar", make_flat_stylebox(style_disabled_color, 2, 2, 2, 2, 6));
	theme->set_stylebox("fill", "ProgressBar", make_flat_stylebox(style_progress_color, 2, 2, 2, 2, 6));
	theme->set_font("font", "ProgressBar", Ref<Font>());
	theme->set_font_size("font_size", "ProgressBar", -1);
	theme->set_color("font_color", "ProgressBar", control_font_hover_color);
	theme->set_color("font_shadow_color", "ProgressBar", Color(0, 0, 0));
	theme->set_color("font_outline_color", "ProgressBar", Color(1, 1, 1));
	theme->set_constant("outline_size", "ProgressBar", 0);
	
	theme->set_stylebox("normal", "TextEdit", style_line_edit);