revert to disabling multipart client with S3 EC

Author: ahmarsuhail

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/DefaultS3ClientFactory.java

@@ -38,6 +38,7 @@
 import software.amazon.awssdk.identity.spi.AwsCredentialsIdentity;
 import software.amazon.awssdk.regions.Region;
 import software.amazon.awssdk.services.s3.S3AsyncClient;
+import software.amazon.awssdk.services.s3.S3AsyncClientBuilder;
 import software.amazon.awssdk.services.s3.S3BaseClientBuilder;
 import software.amazon.awssdk.services.s3.S3Client;
 import software.amazon.awssdk.services.s3.S3Configuration;
@@ -145,11 +146,17 @@ public S3AsyncClient createS3AsyncClient(
         .thresholdInBytes(parameters.getMultiPartThreshold())
         .build();
 
-    return configureClientBuilder(S3AsyncClient.builder(), parameters, conf, bucket)
-        .httpClientBuilder(httpClientBuilder)
-        .multipartConfiguration(multipartConfiguration)
-        .multipartEnabled(parameters.isMultipartCopy())
-        .build();
+    S3AsyncClientBuilder s3AsyncClientBuilder =
+        configureClientBuilder(S3AsyncClient.builder(), parameters, conf, bucket).httpClientBuilder(
+            httpClientBuilder);
+
+    if (!parameters.isClientSideEncryptionEnabled()) {
+      s3AsyncClientBuilder
+          .multipartConfiguration(multipartConfiguration)
+          .multipartEnabled(parameters.isMultipartCopy());
+    }
+
+    return s3AsyncClientBuilder.build();
   }
 
   @Override