Add ~"customer" label to all ~"Gitaly Customer Issue" bugs

What does this MR do and why?

The Gitaly team use issue_templates/Support%20Request.md to handle incoming requests for support from customers which assigns a Gitaly Customer Issue label.

In some cases we can advise the customer how to resolve the issue, however in others we uncover an underlying bug.

If we assign typebug to one of these issues after investigation - it would be useful to also automatically assign the customer bug to help ensure it shows up in relevant reports for triaging

Expected impact & dry-runs

These are strongly recommended to assist reviewers and reduce the time to merge your change.

See https://gitlab.com/gitlab-org/quality/triage-ops/-/tree/master/doc/scheduled#testing-with-a-dry-run on how to perform dry-runs for new policies.

See https://gitlab.com/gitlab-org/quality/triage-ops/-/blob/master/doc/reactive/best_practices.md#use-the-sandbox-to-test-new-processors on how to make sure a new processor can be tested.

• Expected to run against any issue labelled groupgitaly Gitaly Customer Issue typebug
  • These will most likely only occur in the project gitlab-org/gitaly although some may be found in gitlab-org/gitlab or elsewhere if an issue is moved
  • Sample Filter of the issues which should be impacted by this job

✅ https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/3849902703

TRIAGE_POLICY_FILE=policies/groups/gitlab-org/gitaly/gitaly-customer-issues-bugs.yml
TRIAGE_SOURCE_PATH=gitlab-org/gitaly

✅ https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/3849948928

TRIAGE_POLICY_FILE=policies/groups/gitlab-org/gitaly/gitaly-customer-issues-bugs.yml
TRIAGE_SOURCE_TYPE=group
TRIAGE_SOURCE_PATH=gitlab-org

Action items

• If adding environment variables for reactive processors, update config/triage-web.yaml and .gitlab/ci/triage-web.yml
• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels => #g_gitaly
  • Engineering week-in-review