Fix flaky test pause_fileChanged_resumeShouldStartFromBeginning

Author: S-Saranya1

services-custom/s3-transfer-manager/src/it/java/software/amazon/awssdk/transfer/s3/S3TransferManagerUploadPauseResumeIntegrationTest.java

@@ -167,7 +167,10 @@ void pause_fileChanged_resumeShouldStartFromBeginning(S3TransferManager uploadTm
             FileUpload resumedUpload = resumeTm.resumeUploadFile(resumableFileUpload);
             resumedUpload.completionFuture().join();
             verifyMultipartUploadIdNotExist(resumableFileUpload);
-            assertThat(resumedUpload.progress().snapshot().totalBytes()).hasValue(bytes.length);
+
+            // Verify via S3 instead of progress snapshot, which may be empty for cross-TM resume
+            long actualLength = s3.headObject(b -> b.bucket(BUCKET).key(KEY)).contentLength();
+            assertThat(actualLength).isEqualTo(bytes.length);
         } finally {
             Files.write(largeFile.toPath(), originalBytes);
         }