Remove recruiting email from onboarding series

The purpose of this issue is to remove the onboarding email specifically directing users to score their onboaridng experience and to register for an interview session.

This would was originally completed via this issue: gitlab-org/growth/team-tasks#314 (closed)

When this is done, let @jackib know so that the Calendly account can be paused.

Next Steps

Cleaning up the feature flag

• Ensure the onboarding email and related code is removed without breaking the email series. This will require testing.
  • This means removing the experience email and the survey response landing page that it invokes.
• Check if 'iglu:com.gitlab/survey_response/jsonschema/1-0-1' is still needed !92280 (diffs, comment 1025422039) and remove
  • https://gitlab.com/gitlab-org/iglu/-/merge_requests/77
• Ask @alexbuijs (original author) to review
• Create a merge request to remove calendly_invite_link feature flag. Ask for review and merge it.
  • Remove all references to the feature flag from the codebase.
  • Remove the YAML definitions for the feature from the repository.
  • Create a changelog entry.
• Ensure that the cleanup MR has been deployed to both production and canary. If the merge request was deployed before the code cutoff, the feature can be officially announced in a release blog post.
  • /chatops run auto_deploy status <merge-commit-of-cleanup-mr>
• Close the feature issue to indicate the feature will be released in the current milestone.
• If not already done, clean up the feature flag from all environments by running these chatops command in #production channel:
  • /chatops run feature delete calendly_invite_link --dev
  • /chatops run feature delete calendly_invite_link --staging
  • /chatops run feature delete calendly_invite_link
• Update and close the rollout issue #330340 (closed)
• Inform @jackib (to remove the Calendly account).