xds/interop: turn on affinity urlmap tests for go (#27359)

diff --git a/tools/run_tests/xds_k8s_test_driver/tests/url_map/affinity_test.py b/tools/run_tests/xds_k8s_test_driver/tests/url_map/affinity_test.py
index fdbad45..c58d406 100644
--- a/tools/run_tests/xds_k8s_test_driver/tests/url_map/affinity_test.py
+++ b/tools/run_tests/xds_k8s_test_driver/tests/url_map/affinity_test.py
@@ -57,7 +57,7 @@
 
     @staticmethod
     def supported_clients() -> Tuple[str]:
-        return 'cpp', 'java'
+        return 'cpp', 'java', 'go'
 
     @staticmethod
     def client_init_config(rpc: str, metadata: str):
@@ -122,7 +122,7 @@
 
     @staticmethod
     def supported_clients() -> Tuple[str]:
-        return 'cpp', 'java'
+        return 'cpp', 'java', 'go'
 
     @staticmethod
     def client_init_config(rpc: str, metadata: str):