Add commerce_integrations in group definition

What does this MR do and why?

Describe in detail what your merge request does and why.

Related #1131 (closed)

The new group should be added to group-definition.yml

This will enable reporting and automatizations for ~"group::commerce integrations"

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.

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 =>
  • Relevant Slack channels =>
  • Engineering week-in-review