fix(upload): Prevent duplicate progress reports when using Promise.all (#908)

* fix(upload): Prevent duplicate progress reports when using Promise.all

* fmt

plugins/upload/guest-js/index.ts

@@ -15,16 +15,17 @@ async function listenToEventIfNeeded(event: string): Promise<void> {
   if (listening) {
     return await Promise.resolve();
   }
-  return await appWindow
+
-    .listen<ProgressPayload>(event, ({ payload }) => {
+  // We're not awaiting this Promise to prevent issues with Promise.all
-      const handler = handlers.get(payload.id);
+  // the listener will still be registered in time.
-      if (handler != null) {
+  appWindow.listen<ProgressPayload>(event, ({ payload }) => {
-        handler(payload.progress, payload.total);
+    const handler = handlers.get(payload.id);
-      }
+    if (handler != null) {
-    })
+      handler(payload.progress, payload.total);
-    .then(() => {
+    }
-      listening = true;
+  });
-    });
+
+  listening = true;
 }
 
 async function upload(