Repeat warning message for ETA data

src/loaders/shuttle/ApiBasedShuttleRepositoryLoader.ts

@@ -248,6 +248,8 @@ export class ApiBasedShuttleRepositoryLoader implements ShuttleRepositoryLoader
       const etas = this.constructEtasFromJson(json, stopId);
       if (etas !== null) {
         await this.updateEtaDataInRepository(etas);
+      } else {
+        console.warn(`ETA update failed for stop ${stopId} with the following JSON: ${JSON.stringify(json)}`);
       }
     } catch(e: any) {
       throw new ApiResponseError(e.message);