refactor(api): use dto barrel imports

src/data/services/api/metrics_api.ts

@@ -7,8 +7,7 @@
 import { httpClient } from "./http_client";
 import { ApiPath } from "./api_path";
 import { ApiEnvelope, unwrapOptional } from "./response_helper";
-import { AppEvent } from "@/data/dto/metrics/app_event";
-import { PwaEvent } from "@/data/dto/metrics/pwa_event";
+import { AppEvent, PwaEvent } from "@/data/dto/metrics";
 
 export class MetricsApi {
   /**