[web] Fix race condition in initialization of search worker (#1772)

During app init, two worker instances would get created in some cases
and two getInstances raced because of the await. This was causing the
search results to be empty until the page is reloaded (since the files
array was empty in the worker that got assigned, but the files would get
set to the other worker instance that lost the race).

web/apps/photos/src/utils/comlink/ComlinkSearchWorker.ts

@@ -5,11 +5,13 @@ import { type DedicatedSearchWorker } from "worker/search.worker";
 
 class ComlinkSearchWorker {
     private comlinkWorkerInstance: Remote<DedicatedSearchWorker>;
+    private comlinkWorker: ComlinkWorker<typeof DedicatedSearchWorker>;
 
     async getInstance() {
         if (!this.comlinkWorkerInstance) {
-            this.comlinkWorkerInstance =
-                await getDedicatedSearchWorker().remote;
+            if (!this.comlinkWorker)
+                this.comlinkWorker = getDedicatedSearchWorker();
+            this.comlinkWorkerInstance = await this.comlinkWorker.remote;
         }
         return this.comlinkWorkerInstance;
     }