bugfix: part of the connection is not unpacked

[funky-eyes]

Ⅰ. Describe what this PR did

connection 为com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl
如果创建druid连接池时加入了Filter就会变成由ConnectionProxyImpl来实现connection
例如：

 List<Filter> proxyFilters = new ArrayList();
if (!StringUtils.isEmpty(filters) && filters.contains("wall")) {
            WallConfig wallConfig = DruidWallConfigUtil.toWallConfig(dataSourceProperty.getDruid().getWall(), this.druidConfig.getWall());
            WallFilter wallFilter = new WallFilter();
            wallFilter.setConfig(wallConfig);
            proxyFilters.add(wallFilter);
        }
dataSource.setProxyFilters(proxyFilters);

此时datasourcexa中的getconnection获取到的connection是无法创建xaconnection

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-commenter]

Codecov Report

Merging #3071 into develop will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@              Coverage Diff              @@
##             develop    #3071      +/-   ##
=============================================
- Coverage      50.56%   50.55%   -0.02%     
+ Complexity      3102     3101       -1     
=============================================
  Files            599      599              
  Lines          19516    19514       -2     
  Branches        2405     2404       -1     
=============================================
- Hits            9868     9865       -3     
  Misses          8657     8657              
- Partials         991      992       +1     

Impacted Files	Coverage Δ	Complexity Δ
...a/io/seata/rm/datasource/xa/DataSourceProxyXA.java	87.50% <100.00%> (+4.16%)	4.00 <1.00> (ø)
...o/seata/server/coordinator/DefaultCoordinator.java	54.63% <0.00%> (-0.52%)	29.00% <0.00%> (ø%)
...in/java/io/seata/server/session/GlobalSession.java	82.43% <0.00%> (-0.46%)	70.00% <0.00%> (-1.00%)

[wangliang181230]

LGTM

[wangliang181230]

很多数据库连接池框架的连接并没有实现过PooledConnection，很是奇怪。Hikari就是没实现过PooledConnection。
只能unwrap了，唉。

[slievrly]

LGTM

[l81893521]

LGTM