修正插件获取PluginService及PluginConfig的方法

[luanwenfei-venus]

【修复issue】#1239

【修改内容】1、修改插件获取PluginConfig为通过PluginConfigManager::getConfig 2、修改插件获取PluginService为通过PluginServiceManager::getService

【用例描述】不许修改，无功能新增

【自测情况】1、本地静态检查清理情况；

【影响范围】1、对用户的使用有没有影响 2、不涉及文档修改

[codecov]

Codecov Report

Patch coverage: 72.36% and project coverage change: -0.01 ⚠️

Comparison is base (07f7474) 41.64% compared to head (5680849) 41.64%.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #1240      +/-   ##
=============================================
- Coverage      41.64%   41.64%   -0.01%     
- Complexity      3203     3219      +16     
=============================================
  Files            811      817       +6     
  Lines          17939    18032      +93     
  Branches        1952     1961       +9     
=============================================
+ Hits            7471     7509      +38     
- Misses          9531     9578      +47     
- Partials         937      945       +8     

Flag	Coverage Δ
unittests	41.64% <72.36%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ubbo/interceptor/AbstractDirectoryInterceptor.java	0.00% <0.00%> (ø)
...ter/dubbo/interceptor/ClusterUtilsInterceptor.java	0.00% <0.00%> (ø)
...ubbo/interceptor/SpringApplicationInterceptor.java	0.00% <0.00%> (ø)
...er/spring/interceptor/RouteHandlerInterceptor.java	0.00% <0.00%> (ø)
.../dubbo/registry/alibaba/ServiceCenterRegistry.java	0.00% <0.00%> (ø)
...i/dubbo/registry/apache/ServiceCenterRegistry.java	0.00% <0.00%> (ø)
.../interceptor/ApacheInterfaceConfigInterceptor.java	0.00% <0.00%> (ø)
...stry/interceptor/ApplicationConfigInterceptor.java	0.00% <0.00%> (ø)
...stry/interceptor/SpringApplicationInterceptor.java	0.00% <0.00%> (ø)
...awei/flowcontrol/service/InterceptorSupporter.java	41.79% <50.00%> (ø)
... and 27 more

... and 9 files with indirect coverage changes

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