[TEST] Add Windows max macro regression test for OTLP public headers

[ThomsonTan]

Follow up for the comment #3861 (comment)

Changes

• Adds a new regression test in otlp_windows_max_macro_compile_test.cc that defines a Windows-style max macro before including OTLP public headers.
• Prevents recurrence of the Windows/MSVC include-order failure reported in issue v1.25 regression: Build break on Windows with Visual Studio 2022 #3861; no runtime behavior changes, test-only coverage improvement.

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.99%. Comparing base (717cfc9) to head (9f66370).
⚠️ Report is 39 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3865   +/-   ##
=======================================
  Coverage   89.99%   89.99%           
=======================================
  Files         225      225           
  Lines        7170     7170           
=======================================
  Hits         6452     6452           
  Misses        718      718           

see 2 files with indirect coverage changes

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[marcalff]

@ThomsonTan

What this new test will do, is prevent similar bugs to be introduced again in otlp_http_exporter_options.h.

It will not prevent another similar bug to appear in another header file.

Suggestion: implement a new CI check script, similar to tools/check_copyright.sh, that looks for known dangerous coding pattern.

A script running grep -w "max(" on all the source code will pick up the next break.

[ThomsonTan]

script, similar to tools/check_copyright.sh, that looks for known dangerous coding pattern.

A script running grep -w "max(" on all the source code will pick up the next break.

Ok. Close this PR for now as it only validates regression from very specific scenario. Will think on making it general like define it as global before including the API headers.