Update CSharpier to 1.2.6

[pmachapman]

This PR updates CSharpier to the latest version (1.2.6)

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This change is 

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[codecov]

Codecov Report

❌ Patch coverage is 65.62500% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.45%. Comparing base (2ec0029) to head (86820da).
⚠️ Report is 3 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...aAccess/SFDataAccessServiceCollectionExtensions.cs	0.00%	12 Missing ⚠️
.../Realtime/SFRealtimeServiceCollectionExtensions.cs	0.00%	10 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3714   +/-   ##
=======================================
  Coverage   81.44%   81.45%           
=======================================
  Files         620      620           
  Lines       38956    38951    -5     
  Branches     6362     6338   -24     
=======================================
- Hits        31727    31726    -1     
+ Misses       6260     6256    -4     
  Partials      969      969           

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[Nateowami]

@Nateowami reviewed 22 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on pmachapman).