[BugFix] fix num_requests_running after clear_data

[liyonghua0910]

Motivation

1. 当 clear weight 强行打断请求时，因为 engine worker queue 中有残留请求，v1 scheduler 停止调度，不再更新 metrics，导致监控指标异常；
2. 当 clear weight 后调用 clear data 时，逐个请求执行 finish_requests 方法，并调用 free_blocks 来释放缓存块，但此时 prefix cache 已经重置，此时 free_blocks 的报错未捕获，导致该请求清理不完全。

Modifications

在 clear_data 后主动更新一次 metrics，保证 FD 休眠期间 running/waiting 指标清空。同时修复 clear_data 的异常捕获问题。

Usage or Command

Accuracy Tests

Checklist

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  • 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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[paddle-bot]

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