[FIPS 4.0 CHERRY-PICK #2994] Cache peer CA names on client side after handshake (#2994)

[WillChilds-Klein]

Issues:

n/a

Description of changes:

Cherry-pick #2994 .

Testing:

• CI

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 94.73684% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.95%. Comparing base (dd90637) to head (b3086c8).

Files with missing lines	Patch %	Lines
ssl/ssl_x509.cc	84.61%	2 Missing ⚠️
ssl/ssl_cert.cc	66.66%	1 Missing ⚠️

Additional details and impacted files

@@                   Coverage Diff                   @@
##           fips-2025-09-12-lts    #3244      +/-   ##
=======================================================
- Coverage                79.03%   78.95%   -0.09%     
=======================================================
  Files                      667      667              
  Lines                   113339   113382      +43     
  Branches                 16086    16088       +2     
=======================================================
- Hits                     89575    89516      -59     
- Misses                   22966    23066     +100     
- Partials                   798      800       +2     

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