Feature: Add apiTarget and data fields for GraphQL support

[ueman]

📜 Description

Adds two new fields. This is basically a copy of getsentry/sentry-java#2775, but for Dart. I plan to use it for https://pub.dev/packages/sentry_link after this gets merged.

💡 Motivation and Context

Better GraphQL support.

💚 How did you test it?

Tests

📝 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: 82.35% and project coverage change: -0.03 ⚠️

Comparison is base (8ccf782) 90.28% compared to head (c1e831f) 90.25%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1517      +/-   ##
==========================================
- Coverage   90.28%   90.25%   -0.03%     
==========================================
  Files         181      181              
  Lines        5764     5779      +15     
==========================================
+ Hits         5204     5216      +12     
- Misses        560      563       +3     

Impacted Files	Coverage Δ
dart/lib/src/protocol/sentry_response.dart	80.00% <76.92%> (-2.76%)	⬇️
dart/lib/src/protocol/sentry_request.dart	98.30% <100.00%> (+0.12%)	⬆️

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[marandaneto]

Thanks @ueman

Lint:

"summary": "### [~] 20/30 points: code has no errors, warnings, lints, or formatting issues\n\n

\n

\n/tmp/pana_RRRDNM/lib/src/protocol/sentry_request.dart doesn't match the Dart formatter.\n

\n\nTo format your files run: dart format .\n

"

[marandaneto]

LGTM