Change group::workspace to group::organization for Quad Planning

What does this MR do and why?

~group::workspace had been recently renamed to ~group::organization: gitlab-com/www-gitlab-com#14254 (closed)

This MR updates the Quad Planning policy to account for this new name change.

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.

• A successful dry run was completed: https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/3615949501

Action items

• (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 => @lohrc @jennli @at.ramya
  • Relevant Slack channels =>
  • Engineering week-in-review