[BugFix] Fix the issue of redundant logging for certain events in the trace_logger

[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)

We have currently identified an issue in the trace_logger logs where a single request is redundantly logging the following three events: RESOURCE_ALLOCATE_END, REQUEST_SCHEDULE_END, and INFERENCE_START. Further investigation revealed that this is caused by the function _schedule_request_to_worker_v1 logging the timestamps repeatedly after the ENABLE_V1_KVCACHE_SCHEDULER feature was enabled.

Modifications

Added a conditional check before logging events in the _schedule_request_to_worker_v1 method, ensuring events are only logged when the current task type is PREFILL.

Usage or Command

Accuracy Tests

Checklist

• Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
  • You can add new tags based on the PR content, but the semantics must be clear.
• Format your code, run pre-commit before commit.
• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
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[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@9460254). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
fastdeploy/engine/common_engine.py	0.00%	7 Missing ⚠️

Additional details and impacted files

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  Misses             ?    14553           
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