[release-1.20] Suppress 'default value insecure' warning when secure-pod-defaults is enabled.

[knative-prow-robot]

This is an automated cherry-pick of #16218

[knative-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.06%. Comparing base (2f3129a) to head (8928e72).

Additional details and impacted files

@@              Coverage Diff              @@
##           release-1.20   #16220   +/-   ##
=============================================
  Coverage         80.05%   80.06%           
=============================================
  Files               214      214           
  Lines             13281    13281           
=============================================
+ Hits              10632    10633    +1     
+ Misses             2291     2290    -1     
  Partials            358      358           

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[dprotaso]

/hold

[dprotaso]

For context on the hold - I don't want to trigger a point release until we have more substantial changes to include.