theme: decrease list row transition

It was somewhat annoying given the "trace" of it. Decrease
the time to avoid too much "trace"

gtk/theme/Adwaita/_common.scss

@@ -2674,7 +2674,7 @@ GtkScrolledWindow {
 
 // transition
 .list-row, list-row.button {
-  transition: all 300ms $ease-out-quad;
+  transition: all 150ms $ease-out-quad;
   &:hover { transition: none; }
 }