[cherry-pick]Fix APITEST_DB_PROXY_CACHE x509

[YangJiao0817]

Fix APITEST_DB_PROXY_CACHE x509, Because cicd.harbor.vmwarecna uses a self-signed certificate.

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Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

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[codecov]

Codecov Report

Merging #18980 (04b5cb8) into release-2.7.0 (874399f) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@                Coverage Diff                @@
##           release-2.7.0   #18980      +/-   ##
=================================================
- Coverage          66.41%   66.40%   -0.01%     
=================================================
  Files               1012     1012              
  Lines             108652   108652              
  Branches            2677     2677              
=================================================
- Hits               72159    72153       -6     
- Misses             32529    32534       +5     
- Partials            3964     3965       +1     

Flag	Coverage Δ
unittests	66.40% <ø> (-0.01%)	⬇️

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see 4 files with indirect coverage changes

[chlins]

lgtm