Enable assumeImmutableResults in DAST Site Profiles

Set assumeImmutableResults to true in the Apollo provider
for DAST Site Profiles

Refer https://gitlab.com/groups/gitlab-org/-/epics/6025

ee/app/assets/javascripts/security_configuration/dast_profiles/dast_site_profiles/graphql/provider.js

@@ -5,5 +5,5 @@ import createDefaultClient from '~/lib/graphql';
 Vue.use(VueApollo);
 
 export default new VueApollo({
-  defaultClient: createDefaultClient(),
+  defaultClient: createDefaultClient({}, { assumeImmutableResults: true }),
 });