fix: add missing llm_metrics field to tool_parser_v2 test helper

[nv-anants]

The chunk() test helper in tool_parser_v2.rs constructs NvCreateChatCompletionStreamResponse without the llm_metrics field that was added to the struct, breaking the post-merge rust-gpu job with E0063 - https://github.com/ai-dynamo/dynamo/actions/runs/28245372779/job/83683622594

This is a merge-skew failure: the field was introduced by #10512 and the test helper by #10853, each green against its own base.

Summary by CodeRabbit

• Tests
  • Updated streaming chat completion test data to include the latest response field, keeping coverage aligned with current output structure.

[coderabbitai]

Walkthrough

The streaming chat completion test helper now constructs NvCreateChatCompletionStreamResponse with llm_metrics: None.

Changes

OpenAI chat completion stream fixture

Layer / File(s)	Summary
Add llm_metrics to chunk fixture lib/llm/src/protocols/openai/chat_completions/tool_parser_v2.rs	The chunk helper’s NvCreateChatCompletionStreamResponse literal includes llm_metrics: None.

🎯 1 (Trivial) | ⏱️ ~1 minute

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	⚠️ Warning	The description explains the bug and fix, but it omits the required template sections and lacks a Related Issues entry.	Add the required Overview, Details, and Where should reviewer start sections, and complete Related Issues with a linked issue or the no-issue checkbox.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly states the main fix: adding the missing llm_metrics field in the tool_parser_v2 test helper.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[keivenchang]

Thank you Anant, really appreciate it (you're too fast for me).