Add minimal validation for asset_tags

app/Http/Controllers/Assets/AssetsController.php

@@ -102,6 +102,10 @@ class AssetsController extends Controller
     {
         $this->authorize(Asset::class);
 
+        // There are a lot more rules to add here but prevents
+        // errors around `asset_tags` not being present below.
+        $this->validate($request, ['asset_tags' => ['required', 'array']]);
+
         // Handle asset tags - there could be one, or potentially many.
         // This is only necessary on create, not update, since bulk editing is handled
         // differently