Pass the noteable_path when commenting from a PipelineEvent

Context

Closes #1579 (closed)

What does this MR do and why?

Pass the noteable_path when commenting from a PipelineEvent

PipelineEvents are not of kind Noteables (i.e. we cannot write notes into them).

What we want in the case of the RemoveRunE2eOmnibusOnceLabel processor is to comment on the merge request related to the pipeline that the event is related to.

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-policies-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.

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 =>
  • Engineering week-in-review