[BugFix] Fix redundant prompt_logprobs in the second chunk of streaming response when return_token_ids is enabled for v1/completions and fix trace file name

[qwes5s5]

Motivation

💡 If this PR is a Cherry Pick, the PR title needs to follow the format by adding the [Cherry-Pick] label at the very beginning and appending the original PR ID at the end. For example, [Cherry-Pick][CI] Add check trigger and logic(#5191)

💡 如若此PR是Cherry Pick，PR标题需遵循格式，在最开始加上[Cherry-Pick]标签，以及最后面加上原PR ID，例如[Cherry-Pick][CI] Add check trigger and logic(#5191)

• It was reported that when using the v1/completions with return_token_ids enabled in streaming mode, the second output chunk still contains prompt_logprobs. According to the original design, prompt_logprobs should only be included in the first chunk of a streaming response.
• The trace log filename "trace_logger.log" is currently non-standard.

Modifications

• This PR updates the logic for the v1/completions: when return_token_ids is enabled during streaming, the prompt_logprobs output in delta_message is now restricted to ensure it is only sent when intended (typically only in the first chunk).
• Updated the log filename generated by trace_logger to "trace.log".

Usage or Command

curl -X POST "http://0.0.0.0:8000/v1/completions" \
-H "Content-Type: application/json" \
-d '{
  "prompt": "中国的首都是？",
  "return_token_ids":true,
  "stream":true,
  "max_tokens": 5,
  "prompt_logprobs":2
}'

Accuracy Tests

Checklist

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Codecov Report

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