Sentinel Dashboard多副本或重启后规则ID不正常的问题

##Issue Description

Type: *bug report*

### Describe what happened (or what feature you want)

当dashboard为多副本是规则id会出现相同的自增数字id，当dashboard重启后id自增会被重置，导致生成重复的规则id。

### Describe what you expected to happen

希望规则id可以再并发不高的情况下尽量减少重复冲突。

No file, test, or entry point is named in the report. Start by tracing Sentinel Dashboard's rule-ID generation and persistence paths, then examine how IDs behave across multiple dashboard instances and restarts. Done means the relevant tests demonstrate reduced duplicate-ID conflicts in both scenarios.

Written by the indexing model from the issue text.