fix(storage): Use append_object_spec in EnrichSpan for ResumeAppendableUpload (#16296)

Author: bajajneha27

google/cloud/storage/internal/async/connection_tracing.cc

@@ -125,8 +125,7 @@ class AsyncConnectionTracing : public storage::AsyncConnection {
   ResumeAppendableObjectUpload(AppendableUploadParams p) override {
     auto span = internal::MakeSpan(
         "storage::AsyncConnection::ResumeAppendableObjectUpload");
-    EnrichSpan(*span, p.options,
-               p.request.write_object_spec().resource().bucket());
+    EnrichSpan(*span, p.options, p.request.append_object_spec().bucket());
     internal::OTelScope scope(span);
     return impl_->ResumeAppendableObjectUpload(std::move(p))
         .then([oc = opentelemetry::context::RuntimeContext::GetCurrent(),

google/cloud/storage/internal/async/connection_tracing_test.cc

@@ -722,9 +722,12 @@ TEST(ConnectionTracing, ResumeAppendableObjectUploadSuccess) {
 
   EXPECT_CALL(*mock, ResumeAppendableObjectUpload).WillOnce(expect_context(p));
   auto actual = MakeTracingAsyncConnection(std::move(mock));
+  google::storage::v2::BidiWriteObjectRequest request;
+  request.mutable_append_object_spec()->set_bucket("test-bucket");
   auto f = actual
                ->ResumeAppendableObjectUpload(
-                   AsyncConnection::AppendableUploadParams{})
+                   AsyncConnection::AppendableUploadParams{request,
+                                                           TracingEnabled()})
                .then(expect_no_context);
 
   auto mock_writer = std::make_unique<MockAsyncWriterConnection>();