gnome-shell: Remove -shell-close-overlap property

Based on upstream commit:
https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/c5634335b04133f3c0e84aa3c8081c5fcc57c7fd

Author: jnsh

common/gnome-shell/3.38/sass/_common.scss

@@ -1545,7 +1545,6 @@ StScrollBar {
   color: $destructive_fg_color;
   height: 22px;
   width: 22px;
-  -shell-close-overlap: 9px;
   padding: 0;
 
   & > StIcon { icon-size: 16px; }