Ruby: enable blocking test with Forwarded header (#5481)

Author: y9v

manifests/ruby.yml

@@ -440,7 +440,7 @@ tests/:
       Test_BlockingGraphqlResolvers: v2.4.0
       Test_Blocking_client_ip: v1.0.0
       Test_Blocking_client_ip_with_K8_private_ip: missing_feature
-      Test_Blocking_client_ip_with_forwarded: missing_feature
+      Test_Blocking_client_ip_with_forwarded: v2.22.0.dev
       Test_Blocking_request_body: v1.0.0
       Test_Blocking_request_body_multipart: v1.0.0
       Test_Blocking_request_cookies: v1.0.0