Remove use of internal API

Note: This is in codee that will be deleted.

Author: dagnir

services/sns/src/main/java/software/amazon/awssdk/services/sns/internal/messagemanager/DefaultSnsMessageManager.java

@@ -20,7 +20,6 @@
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 import software.amazon.awssdk.annotations.SdkInternalApi;
-import software.amazon.awssdk.core.internal.http.loader.DefaultSdkHttpClientBuilder;
 import software.amazon.awssdk.http.SdkHttpClient;
 import software.amazon.awssdk.http.SdkHttpConfigurationOption;
 import software.amazon.awssdk.services.sns.messagemanager.MessageManagerConfiguration;
@@ -88,7 +87,7 @@ private DefaultSnsMessageManager(DefaultBuilder builder) {
             this.httpClient = configuration.httpClient();
             this.shouldCloseHttpClient = false;
         } else {
-            this.httpClient = new DefaultSdkHttpClientBuilder().buildWithDefaults(createHttpDefaults());
+            this.httpClient = null;
             this.shouldCloseHttpClient = true;
         }