fix(showcase): use NoCredentialsProvider in remaining ITOtelErrorType tests

Author: diegomarquezp

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

@@ -325,6 +325,7 @@ void testTracing_clientConnectionError_ConnectException_grpc() throws Exception
     SpanTracerFactory tracingFactory = new SpanTracerFactory(openTelemetrySdk);
     EchoSettings grpcEchoSettings =
         EchoSettings.newBuilder()
+            .setCredentialsProvider(NoCredentialsProvider.create())
             .setTransportChannelProvider(
                 EchoSettings.defaultGrpcTransportProviderBuilder()
                     .setChannelConfigurator(ManagedChannelBuilder::usePlaintext)
@@ -355,6 +356,7 @@ void testTracing_clientConnectionError_UnknownHost_grpc() throws Exception {
     SpanTracerFactory tracingFactory = new SpanTracerFactory(openTelemetrySdk);
     EchoSettings grpcEchoSettings =
         EchoSettings.newBuilder()
+            .setCredentialsProvider(NoCredentialsProvider.create())
             .setTransportChannelProvider(
                 EchoSettings.defaultGrpcTransportProviderBuilder()
                     .setChannelConfigurator(ManagedChannelBuilder::usePlaintext)
@@ -451,6 +453,7 @@ void testTracing_clientTimeout_DeadlineExceededException_grpc() throws Exception
 
       EchoSettings grpcEchoSettings =
           EchoSettings.newBuilder()
+              .setCredentialsProvider(NoCredentialsProvider.create())
               .setTransportChannelProvider(
                   EchoSettings.defaultGrpcTransportProviderBuilder()
                       .setChannelConfigurator(ManagedChannelBuilder::usePlaintext)