how to config max RT in nacos and use in client

## Issue Description

how to config max RT in nacos and use in client

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

1.目前官方文档是通过启动配置项配置熔断降级超时最大时间 -Dcsp.sentinel.statistic.max.rt，因为sentinel默认最大4900ms
2.在实际项目中有一个服务需要超过4900 ms，但是不想在启动sentinel的时候配置，而是类似于在nacos动态配置项配置这个参数
3.请问这个参数如何配置和在client如何读取
### Describe what you expected to happen

可以动态配置这个参数，比如在yml里边设置
### How to reproduce it (as minimally and precisely as possible)

1.目前官方文档是通过启动配置项配置熔断降级超时最大时间 -Dcsp.sentinel.statistic.max.rt，因为sentinel默认最大4900ms
2.在实际项目中有一个服务需要超过4900 ms，但是不想在启动sentinel的时候配置，而是类似于在nacos动态配置项配置这个参数
3.请问这个参数如何配置和在client如何读取

### Tell us your environment

sentinel 1.8.0
### Anything else we need to know?

no

No source files or tests are identified. Start by reading the Sentinel documentation and the startup property -Dcsp.sentinel.statistic.max.rt, then trace how client configuration is loaded and whether Nacos or YAML is covered. Done means the maximum RT can be configured dynamically and read by the client.

Written by the indexing model from the issue text.