chore: make the owlbot postprocessor check non-required (#1686)

* chore: make the owlbot postprocessor check non-required

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

.github/sync-repo-settings.yaml

@@ -16,7 +16,6 @@ branchProtectionRules:
       - units (11)
       - 'Kokoro - Test: Integration'
       - cla/google
-      - OwlBot Post Processor
       - 'Kokoro - Test: Java GraalVM Native Image'
       - 'Kokoro - Test: Java 17 GraalVM Native Image'
   - pattern: java7