Add an e2e test for suggested reviewers

What does this MR do and why?

Adds a new basic test of the Suggested Reviewers dropdown that appears in merge requests.

This test uses a merge request that was manually created in the GitLab QA project (gitlab-qa!1056). It can't be run in the dot com environments using new blank projects because model training takes time after the suggested reviewers feature is enabled.

Depends on !101308 (merged)
Part of gitlab-org/quality/testcases#3245 (closed)

How to set up and validate locally

CI_PROJECT_NAME="production" \
GITLAB_USERNAME="gitlab-qa" \
GITLAB_PASSWORD="<from 1Password>" \
GITLAB_QA_ACCESS_TOKEN="<from 1Password>" \
GITLAB_QA_USER_AGENT="<from 1Password>" \
bundle exec bin/qa Test::Instance::All https://gitlab.com -- qa/specs/features/ee/browser_ui/14_model_ops/suggested_reviewer_spec.rb

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Test results

ModelOps
  Suggested Reviewers
[Oct 13 2022 09:13:37 AEDT (QA Tests)] INFO  -- Starting test: ModelOps Suggested Reviewers suggests reviewers
[Oct 13 2022 09:13:39 AEDT (QA Tests)] INFO  -- filling :login_field with "gitlab-qa"
[Oct 13 2022 09:13:39 AEDT (QA Tests)] INFO  -- clicking the coordinates of :login_field
[Oct 13 2022 09:13:40 AEDT (QA Tests)] INFO  -- filling :password_field with "*****"
[Oct 13 2022 09:13:40 AEDT (QA Tests)] INFO  -- clicking the coordinates of :password_field
[Oct 13 2022 09:13:46 AEDT (QA Tests)] INFO  -- clicking :sign_in_button
[Oct 13 2022 09:13:49 AEDT (QA Tests)] INFO  -- Visiting QA::Resource::MergeRequest at https://gitlab.com/gitlab-org/gitlab-qa/-/merge_requests/1056
[Oct 13 2022 09:13:52 AEDT (QA Tests)] INFO  -- clicking :reviewers_edit_button
      suggests reviewers

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1 examples, 0 failures