fix(samples): sass errors

Author: desig9stein

src/app/layouts/expansion-panel/expansion-styling/expansion-styling.component.scss

@@ -7,7 +7,8 @@ $my-secondary-color: #ffd351;
 // Create custom palette
 $my-color-palette: palette(
     $primary: $my-primary-color,
-    $secondary: $my-secondary-color
+    $secondary: $my-secondary-color,
+	$surface: #000
 );
 
 // Create expansion panel theme

src/app/tree-grid/tree-grid-row-edit-style/tree-grid-row-edit-style.component.scss

@@ -14,6 +14,6 @@ $banner-theme: banner-theme(
     @include palette($purple-palette);
 
     ::ng-deep {
-        @include css-vars(css-vars);
+        @include css-vars($banner-theme);
     }
 }