test(logging): fix missing credentials in Actionable Errors tests

Added `NoCredentialsProvider.create()` to the `stubSettingsBuilder` in `testHttpJson_clientLevelFailureAttributes` and `testGrpc_clientLevelFailureAttributes` to prevent test failures in environments without Application Default Credentials.

Author: westarle

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

@@ -215,6 +215,7 @@ void testHttpJson_clientLevelFailureAttributes() throws Exception {
             .setMaxAttempts(1)
             .build());
     stubSettingsBuilder.setTracerFactory(new LoggingTracerFactory());
+    stubSettingsBuilder.setCredentialsProvider(NoCredentialsProvider.create());
     stubSettingsBuilder.setEndpoint(TestClientInitializer.DEFAULT_HTTPJSON_ENDPOINT);
 
     try (com.google.showcase.v1beta1.stub.EchoStub stub = stubSettingsBuilder.build().createStub();
@@ -266,6 +267,7 @@ void testGrpc_clientLevelFailureAttributes() throws Exception {
             .setMaxAttempts(1)
             .build());
     stubSettingsBuilder.setTracerFactory(new LoggingTracerFactory());
+    stubSettingsBuilder.setCredentialsProvider(NoCredentialsProvider.create());
     stubSettingsBuilder.setEndpoint(TestClientInitializer.DEFAULT_GRPC_ENDPOINT);
 
     try (com.google.showcase.v1beta1.stub.EchoStub stub = stubSettingsBuilder.build().createStub();