Enable `assumeImmutableResults` on the Projects Issue tracker

This commit solves https://gitlab.com/gitlab-org/gitlab/-/issues/338433
It enables `assumeImmutableResults` on the Projects Issue tracker.

app/assets/javascripts/issues_list/index.js

@@ -24,8 +24,7 @@ export function mountJiraIssuesListApp() {
   }
 
   Vue.use(VueApollo);
-
-  const defaultClient = createDefaultClient();
+  const defaultClient = createDefaultClient({}, { assumeImmutableResults: true });
   const apolloProvider = new VueApollo({
     defaultClient,
   });