fix(drawer): Temporary drawer is below toolbar (#925)

Author: touficbatache

packages/mdc-drawer/temporary/mdc-temporary-drawer.scss

@@ -34,7 +34,7 @@
   pointer-events: none;
   box-sizing: border-box;
   contain: strict;
-  z-index: 3;
+  z-index: 5;
 
   /* Shaded background */
   &::before {