[BUGFIX] Add z-index to resetbanner trigger icon

Related: T3DEMO-307

src/extensions/site_t3demo/Resources/Private/Scss/_zindex.scss

@@ -12,13 +12,13 @@ $z-index-list: (
 	'.b_header__meta',
 	'.b_header',
 	'.b_resetbanner__overlay',
-	'.b_resetbanner'
+	'.b_resetbanner',
+	'.b_resetbanner__trigger'
 );
 
 $z-index-defaults: (
 );
 
-
 // create all z-index values
 $temp-z: 10;
 @each $class in $z-index-list {