gtk4: Add initial styling for libadwaita widgets

Author: jnsh

common/gtk-4.0/sass/_common.scss

@@ -496,6 +496,7 @@ button {
       padding-right: 12px;
     }
 
+    %image_text_button,
     &.text-button.image-button {
       padding-left: 5px;
       padding-right: 5px;
@@ -688,6 +689,7 @@ button {
 
   .linked.vertical > & { @extend %linked_vertical; }
 
+  %circular_button,
   menubutton.circular &,
   &.circular { // force circular button shape
     min-width: 24px;