[draft] deps(ffigen): pin ffigen to 19.0.0

[buenaflor]

📜 Description

Use latest compatible ffigen version

Make sure it doesnt affect functionalities and doesn't crash

TODO: re-generate sentry-native bindings

💡 Motivation and Context

Tiny step towards #1444

💚 How did you test it?

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• No new PII added or SDK only sends newly added PII if sendDefaultPii is enabled
• I updated the docs if needed
• All tests passing
• No breaking changes

🔮 Next steps

[codecov]

Codecov Report

❌ Patch coverage is 42.85714% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.50%. Comparing base (e10be73) to head (01e7c23).

Files with missing lines	Patch %	Lines
...tter/lib/src/native/cocoa/sentry_native_cocoa.dart	42.85%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3163      +/-   ##
==========================================
+ Coverage   87.79%   89.50%   +1.71%     
==========================================
  Files         291       96     -195     
  Lines        9888     3431    -6457     
==========================================
- Hits         8681     3071    -5610     
+ Misses       1207      360     -847     

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