fix(langgraph): add missing attributes to invoke_agent span

[shellmayr]

• Add missing attributes to invoke_agent span:
  gen_ai.request.model
  gen_ai.response.model
  gen_ai.usage.input_tokens
  gen_ai.usage.output_tokens
  gen_ai.usage.total_tokens
  gen_ai.request.messages

Closes TET-1456

[linear]

TET-1456 Py Langgraph - attributes missing

[codecov]

Codecov Report

❌ Patch coverage is 57.79817% with 46 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.77%. Comparing base (828e513) to head (d7fa0e4).
⚠️ Report is 2 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/integrations/langgraph.py	57.79%	31 Missing and 15 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5168      +/-   ##
==========================================
- Coverage   83.94%   83.77%   -0.18%     
==========================================
  Files         181      181              
  Lines       18335    18451     +116     
  Branches     3259     3304      +45     
==========================================
+ Hits        15391    15457      +66     
- Misses       1939     1970      +31     
- Partials     1005     1024      +19     

Files with missing lines	Coverage Δ
sentry_sdk/integrations/langgraph.py	70.00% <57.79%> (-7.09%)	⬇️

... and 6 files with indirect coverage changes

[shellmayr]

Closing - the Python SDK team will take care of adding support for v1 of Langgraph, and in the course of it, these changes will probably be added. For the record, this PR was a first attempt and not everything works yet, so it's probably not very useful as reference.