Themes(icecream,food): rework diet options, show advanced diet options in icecream layer

src/UI/Popup/GroupedView.svelte

@@ -38,6 +38,7 @@
       }
     }
   }
+  let isTesting = state.featureSwitchIsTesting
 </script>
 
 {#if tagRenderings.length > 0}
@@ -57,4 +58,11 @@
       {/each}
     </AccordionSingle>
   </div>
+{:else if $isTesting}
+  <div class="alert">
+    Group not loaded as no labels match {labels.join(", ")}
+    {#if blacklist.length > 0}
+      (with blacklist {blacklist.join(", ")})
+    {/if}
+  </div>
 {/if}