gnome-shell: Add default styling for screen shield notification count

Based on upstream commit:
https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/9eff9adaae7e0dd92d431438587e65b3b04af2d7

#72

Author: drakkar1969

common/gnome-shell/3.36/sass/_common.scss

@@ -2657,7 +2657,11 @@ StScrollBar {
 
 .unlock-dialog-notification-count-text {
   font-weight: bold;
-  padding: 0px 12px;
+  padding: 0 6px;
+  color: $osd_bg_color;
+  background-color: transparentize($osd_fg_color, 0.7);
+  border-radius: 99px;
+  margin-right: 12px;
 }
 
 .screen-shield-background { //just the shadow, really