fix(rn,dynamic-branding) fix handling bogus response from the backend

react/features/dynamic-branding/middleware.native.ts

@@ -32,10 +32,13 @@ MiddlewareRegistry.register(store => next => action => {
             inviteDomain
         };
 
+        // The backend may send an empty string, make sure we skip that.
+        if (Array.isArray(avatarBackgrounds)) {
             // TODO: implement support for gradients.
             action.value.avatarBackgrounds = avatarBackgrounds.filter(
                 (color: string) => !color.includes('linear-gradient')
             );
+        }
 
         break;
     }