Allow codeowner validation to fail on CI

[sarah-witt]

What does this PR do?

• allows codeowners validation to fail when run on the CI

Motivation

Additional Notes

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached

[codecov]

Codecov Report

Merging #7207 into master will decrease coverage by 4.60%.
The diff coverage is n/a.

Impacted Files	Coverage Δ
...xtras/datadog_checks/linux_proc_extras/__init__.py
directory/tests/conftest.py
oracle/datadog_checks/oracle/oracle.py
prometheus/datadog_checks/prometheus/__init__.py
lighttpd/datadog_checks/lighttpd/__about__.py
tokumx/tests/metrics.py
cassandra/datadog_checks/cassandra/__about__.py
...ctory/datadog_checks/active_directory/__about__.py
activemq_xml/tests/common.py
spark/tests/common.py
... and 805 more