fix(web): downloads aborted when switching assets in the viewer (#32663)

* fix(web): downloads aborted when switching assets in the viewer

The service worker also handled the download request, so the viewer cancelling its image urls killed the download too. Only handle image requests there.

* chore: clean up

---------

Co-authored-by: Jason Rasmussen <jason@rasm.me>
(cherry picked from commit 8c3fdda7ead1a70158780e45a67a11413b208dba)

web/src/service-worker/index.ts

@@ -13,8 +13,11 @@ const handleInstall = (event: ExtendableEvent) => {
   event.waitUntil(sw.skipWaiting());
 };
 
+const isImageTagRequest = (event: FetchEvent) =>
+  event.request.method === 'GET' && event.request.destination === 'image';
+
 const handleFetch = (event: FetchEvent): void => {
-  if (event.request.method !== 'GET') {
+  if (!isImageTagRequest(event)) {
     return;
   }