Kyverno policy CI bug fixes

Two tests:

• Mattermost, non-debug: https://repo1.dso.mil/platform-one/big-bang/pipeline-templates/package-validation/-/jobs/17769631
• Podinfo, debug: https://repo1.dso.mil/platform-one/big-bang/pipeline-templates/package-validation/-/jobs/17769637

Changes in this MR:

• Adds verbose mode to kyverno apply when DEBUG is on
• Captures exit code of kyverno apply rather than exiting immediately: this allows us to run all policy checks and output results before failing
• DRYs up the logic around testing default values (moves out of the if/else since we always run this)
• Adjusts the find command and logic around detecting policies to ensure we remove non-policy files (prevents random warnings)
• Adds default values check for package specific policies