[Cherry-pick][BugFix]fix console log metrics waitting queue count

[CSWYF3634076]

Motivation

cherry-pick from #6432 to release/2.5

前置PR #6339 #6413
当前控制台打印的metrics信息使用的是len(self.waiting)，但这个值并不是实际的等待请求的数量

Modifications

使用 len(self.waiting) + getattr(self.scheduler, "get_unhandled_request_num", None) 来精确计算等待请求的数量
this PR

Usage or Command

no

Accuracy Tests

no

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.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

[paddle-bot]

Thanks for your contribution!

[codecov-commenter]

Codecov Report

❌ Patch coverage is 89.18919% with 4 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (release/2.5@582e52f). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
fastdeploy/engine/common_engine.py	83.33%	2 Missing ⚠️
fastdeploy/engine/sched/resource_manager_v1.py	92.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@              Coverage Diff               @@
##             release/2.5    #6453   +/-   ##
==============================================
  Coverage               ?   68.36%           
==============================================
  Files                  ?      391           
  Lines                  ?    52753           
  Branches               ?     8213           
==============================================
  Hits                   ?    36062           
  Misses                 ?    14064           
  Partials               ?     2627           

Flag	Coverage Δ
GPU	68.36% <89.18%> (?)

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