[Storage] Update Get-AzStorageFileContent download offset and content length calc logic (#24600)

* Update offset logic

* Update ChangeLog.md

---------

Co-authored-by: NanxiangLiu <33285578+Nickcandy@users.noreply.github.com>

Author: yifanz7

src/Storage/Storage.Management/ChangeLog.md

@@ -19,6 +19,8 @@
 -->
 ## Upcoming Release
 * Fixed object replication policy time format parsing issue [#24434]
+* Updated download offset and content length calculation logic for downloading files 
+    - `Get-AzStorageFileContent`
 
 ## Version 6.1.3
 * Introduced secrets detection feature to safeguard sensitive data.

src/Storage/Storage/File/Cmdlet/GetAzureStorageFileContent.cs

@@ -340,8 +340,8 @@ await DataMovementTransferHelper.DoTransfer(() =>
                                     downloadOptions.Range = new HttpRange(downloadOffset, contentSize);
                                     ShareFileDownloadInfo download = fileClientToBeDownloaded.Download(downloadOptions, cancellationToken: this.CmdletCancellationToken);
                                     download.Content.CopyTo(stream);
-                                    downloadOffset += contentSize;
-                                    contentLenLeft -= contentSize;
+                                    downloadOffset += download.ContentLength;
+                                    contentLenLeft -= download.ContentLength;
                                     progressHandler.Report(downloadOffset);
                                 }
                             }