Exclude `@GitLabDuo` from impacting state on merge request homepage

Problem to Solve

In this comment it was identified that until we potentially support request changes or approvals merge requests where GitLab Duo is a reviewer, get hung in states of the new merge request homepage.

Proposal

We should remove @GitLabDuo from impacting the review states of the homepage. Essentially assuming that it doesn't exist and only "non-bot" users impact it.