Add missing attributes in Langgraph 1.x

[sentrivana]

• These missing attributes were found by the automatic testing tool for AI integrations
• There is no customer request / complaint that I know of related to this
• Some of these attributes were definitely working pre-v1, so we should probably look at this holistically in the context of adding support for langgraph v1

Test Results:

Error: Fixture validation failed:
    invoke_agent (gen_ai.invoke_agent):
       gen_ai.request.model: missing
       gen_ai.response.model: missing
       gen_ai.usage.input_tokens: missing
       gen_ai.usage.output_tokens: missing
       gen_ai.usage.total_tokens: missing
       gen_ai.request.messages: missing
    llm_call (gen_ai.chat):
       gen_ai.response.model: missing

With these package versions:

sentry-sdk==2.43.0
langgraph==1.0.3
langchain-openai>=1.0.0

TET-1456