Add validation for --benchmark-samples to prevent crash with zero value

[chanmyae09]

Fixes #3040

Summary
Added validation to reject --benchmark-samples 0 which was causing a segmentation fault.

Changes

• Added 'setBenchmarkSamples' validation function in 'src/catch2/internal/catch_commandline.cpp'
• Function checks if the value is 0 and returns an error message instead of allowing the crash
• Follows the same pattern as existing validators like 'setShardCount'

Testing
Tested with a benchmark test case - now shows error message "Benchmark samples must be greater than 0" instead of crashing with SIGSEGV.

[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.03%. Comparing base (33e6fd2) to head (84a8fc4).
⚠️ Report is 3 commits behind head on devel.

Additional details and impacted files

@@            Coverage Diff             @@
##            devel    #3041      +/-   ##
==========================================
- Coverage   91.05%   91.03%   -0.03%     
==========================================
  Files         202      202              
  Lines        8716     8725       +9     
==========================================
+ Hits         7936     7942       +6     
- Misses        780      783       +3     

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[horenmar]

Needs an automated test.