Remove AdapterType.PROXY_RANDOM (#36635)

Author: terrymanu

test/e2e/sql/src/test/resources/env/it-env.properties

@@ -26,7 +26,7 @@ it.scenarios=db,tbl,readwrite_splitting,encrypt,shadow,dbtbl_with_readwrite_spli
 # it.cluster.env.type=DOCKER,NATIVE
 it.cluster.env.type=DOCKER
 
-# it.cluster.adapters=jdbc,proxy,proxy_random
+# it.cluster.adapters=jdbc,proxy
 it.cluster.adapters=proxy
 
 # it.cluster.databases=MySQL,PostgreSQL,openGauss,Hive