fix: Add box shadow to form messages (#810)

* fix: Add box shadow to form messages

* test: update visual regression test images

Co-authored-by: deno <mladen.droshev@sap.com>

src/form-message.scss

@@ -20,6 +20,7 @@ $block: #{$fd-namespace}-form-message;
   line-height: normal;
   color: var(--sapTextColor);
   white-space: pre-line !important;
+  box-shadow: var(--sapContent_Shadow1);
 
   @include fd-rtl() {
     right: 0;