[Storage] Fix delete immutable blob will give incorrect prompt (Azure#14691)

Author: blueww

src/Storage/Storage.Management/ChangeLog.md

@@ -18,6 +18,8 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
+* Fixed an issue that delete immutable blob will prompt incorrect message.
+    - `Remove-AzStorageAccount`
 * Fixed copy blob fail with source context as Oauth [#14662]
     -  `Start-AzStorageBlobCopy`
 

src/Storage/Storage/Blob/Cmdlet/RemoveAzureStorageBlob.cs

@@ -181,7 +181,7 @@ internal async Task RemoveAzureBlob(long taskId, IStorageBlobManagement localCha
             }
             catch (StorageException e)
             {
-                if (e.IsConflictException() && retryDeleteSnapshot)
+                if (e.IsConflictException() && e.RequestInformation.ErrorCode.Equals("SnapshotsPresent", StringComparison.InvariantCultureIgnoreCase) && retryDeleteSnapshot)
                 {
                     //If x-ms-delete-snapshots is not specified on the request and the blob has associated snapshots, the Blob service returns status code 409 (Conflict).
                     retryDeleteSnapshot = true;