[Bug Fix] Fix bug for caching output when preempted

[rainyfly]

Motivation

当请求被抢占时，此时由于资源被释放，不应该调用cache_output_tokens

Modifications

如果请求在抢占后待重调度的集合中，不调用cache_output_tokens

Usage or Command

None

Accuracy Tests

None

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.
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• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
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[paddle-bot]

Thanks for your contribution!

[Copilot]

Pull request overview

此PR修复了在请求被抢占(preempted)时仍然缓存输出tokens的bug。当任务处于等待重新调度状态时，不应该缓存其输出tokens，否则可能导致缓存状态不一致。

• 在缓存输出tokens之前添加了对to_be_rescheduled_request_id_set的检查
• 确保被抢占的请求不会错误地缓存其输出tokens

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@9f4512c). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
fastdeploy/output/token_processor.py	0.00%	1 Missing ⚠️

Additional details and impacted files

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Flag	Coverage Δ
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