[BugFix] skip model executing after clearing/updating is done

[liyonghua0910]

Motivation

对于 EP 模型，清除权重后的下一次权重更新，会直接执行一次 event_loop_normal 后半段的 execute_model，而此时 weight/cache 都还没有重建，导致执行出错。

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Modifications

在权重清除/更新后，让 worker 跳过后半段的执行，回到 event_loop_normal 的开头，重新读取状态信号。此项改动对于权重清除场景是必要的，对于权重更新场景也是无害的。

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]]
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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!

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@d67388a). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
fastdeploy/worker/worker_process.py	0.00%	1 Missing ⚠️

Additional details and impacted files

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  Hits               ?    24993           
  Misses             ?    14255           
  Partials           ?     1890           

Flag	Coverage Δ
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