[E2E] PROMOTE TO BLOCKING: duo_chat_spec.rb

What does this MR do?

Promotes the following e2e tests to the blocking bucket:

1. Ai-powered Duo Chat when initiating Duo Chat on GitLab.com behaves like Duo Chat gets a response back from Duo Chat | Testcase | Spec metrics

This MR was created based on data from reliable e2e test report: #500963 (closed)

(This MR was automatically generated by gitlab_quality-test_tooling at 2024-10-28 02:06:35 UTC)