test(logging): fix missing exception in clientLevelFailureAttributes tests

Changed the endpoint for `testHttpJson_clientLevelFailureAttributes` and `testGrpc_clientLevelFailureAttributes` to `localhost:1` instead of `DEFAULT_HTTPJSON_ENDPOINT` and `DEFAULT_GRPC_ENDPOINT`.
Since the showcase server is running during integration tests, sending an empty `EchoRequest` to the default endpoint succeeds without throwing an `ApiException`, causing the `assertThrows` assertion to fail. By pointing to a bad endpoint, we ensure a network exception is always thrown and the client-level failure attributes are properly populated and logged.

Author: westarle

sdk-platform-java/java-showcase/gapic-showcase/src/test/java/com/google/showcase/v1beta1/it/logging/ITActionableErrorsLogging.java

@@ -216,7 +216,7 @@ void testHttpJson_clientLevelFailureAttributes() throws Exception {
             .build());
     stubSettingsBuilder.setTracerFactory(new LoggingTracerFactory());
     stubSettingsBuilder.setCredentialsProvider(NoCredentialsProvider.create());
-    stubSettingsBuilder.setEndpoint(TestClientInitializer.DEFAULT_HTTPJSON_ENDPOINT);
+    stubSettingsBuilder.setEndpoint("localhost:1");
 
     try (com.google.showcase.v1beta1.stub.EchoStub stub = stubSettingsBuilder.build().createStub();
         EchoClient client = EchoClient.create(stub)) {
@@ -268,7 +268,7 @@ void testGrpc_clientLevelFailureAttributes() throws Exception {
             .build());
     stubSettingsBuilder.setTracerFactory(new LoggingTracerFactory());
     stubSettingsBuilder.setCredentialsProvider(NoCredentialsProvider.create());
-    stubSettingsBuilder.setEndpoint(TestClientInitializer.DEFAULT_GRPC_ENDPOINT);
+    stubSettingsBuilder.setEndpoint("localhost:1");
 
     try (com.google.showcase.v1beta1.stub.EchoStub stub = stubSettingsBuilder.build().createStub();
         EchoClient client = EchoClient.create(stub)) {