change private K8s service to be a headless service

[izabelacg]

Related to #13201

Proposed Changes

• change private K8s service to be a headless service

Release Note

The Private Kubernetes service has been transitioned to a headless service, resulting in the freeing up of an iptable entry on a node.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.75%. Comparing base (c2d0af1) to head (6bd9a10).
Report is 109 commits behind head on main.

❗ Current head 6bd9a10 differs from pull request most recent head 5a97964

Please upload reports for the commit 5a97964 to get more accurate results.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15170      +/-   ##
==========================================
+ Coverage   84.11%   84.75%   +0.64%     
==========================================
  Files         213      218       +5     
  Lines       16783    13470    -3313     
==========================================
- Hits        14117    11417    -2700     
+ Misses       2315     1684     -631     
- Partials      351      369      +18     

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[izabelacg]

/hold for review

[dprotaso]

/lgtm
/approve

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dprotaso, izabelacg

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[dprotaso]

/hold cancel