fix: remove unused getSpanName and visibility comment

Author: blakeli0

gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/HttpJsonCallableFactory.java

@@ -45,7 +45,6 @@
 import com.google.api.gax.rpc.UnaryCallSettings;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.api.gax.tracing.ApiTracerContext;
-import com.google.api.gax.tracing.SpanName;
 import com.google.api.gax.tracing.TracedUnaryCallable;
 import javax.annotation.Nonnull;
 
@@ -222,11 +221,6 @@ ServerStreamingCallable<RequestT, ResponseT> createServerStreamingCallable(
     return callable.withDefaultCallContext(clientContext.getDefaultCallContext());
   }
 
-  @InternalApi("Visible for testing")
-  static SpanName getSpanName(@Nonnull ApiMethodDescriptor<?, ?> methodDescriptor) {
-    return SpanName.of(getApiTracerContext(methodDescriptor));
-  }
-
   static ApiTracerContext getApiTracerContext(@Nonnull ApiMethodDescriptor<?, ?> methodDescriptor) {
     return ApiTracerContext.newBuilder()
         .setFullMethodName(methodDescriptor.getFullMethodName())

gax-java/gax/src/main/java/com/google/api/gax/tracing/ObservabilityAttributes.java

@@ -86,6 +86,4 @@ public class ObservabilityAttributes {
   public static final String URL_TEMPLATE_ATTRIBUTE = "url.template";
 
   public static final String DESTINATION_RESOURCE_ID_ATTRIBUTE = "gcp.resource.destination.id";
-
-  // Visible for testing
 }