fix(ai): Do not consume anthropic streaming stop

[colin-sentry]

The old functionality wouldn't re-emit the stop message for streaming Anthropic calls.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.49%. Comparing base (8b40aa0) to head (8efee7d).
Report is 1 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4232      +/-   ##
==========================================
- Coverage   79.52%   79.49%   -0.03%     
==========================================
  Files         141      141              
  Lines       15810    15808       -2     
  Branches     2704     2702       -2     
==========================================
- Hits        12573    12567       -6     
- Misses       2378     2382       +4     
  Partials      859      859              

Files with missing lines	Coverage Δ
sentry_sdk/integrations/anthropic.py	85.29% <100.00%> (+0.99%)	⬆️

... and 4 files with indirect coverage changes

[antonpirker]

Thanks!