Enable `assumeImmutableResults` in sast provider

This commit solves https://gitlab.com/gitlab-org/gitlab/-/issues/331273
It enables `assumeImmutableResults` in the security_configuration sast provider.

ee/app/assets/javascripts/security_configuration/sast/index.js

@@ -13,7 +13,7 @@ export default function init() {
   Vue.use(VueApollo);
 
   const apolloProvider = new VueApollo({
-    defaultClient: createDefaultClient(),
+    defaultClient: createDefaultClient({}, { assumeImmutableResults: true }),
   });
 
   const {