add missing using statement

Author: Andrew Omondi

src/Microsoft.Graph.Core/Tasks/LargeFileUploadTask.cs

@@ -75,7 +75,7 @@ internal static IUploadSession ExtractSessionFromParsable(IParsable uploadSessio
                 throw new ArgumentException("The Parsable does not contain the 'uploadUrl' property");
 
             // convert to local type as we don't have the type info for the upload session just that it implements IParsable
-            var uploadSessionStream = KiotaSerializer.SerializeAsStream(CoreConstants.MimeTypeNames.Application.Json, uploadSession, false);// just in case there's a backing store 
+            using var uploadSessionStream = KiotaSerializer.SerializeAsStream(CoreConstants.MimeTypeNames.Application.Json, uploadSession, false);// just in case there's a backing store 
             var uploadSessionJsonNode = new JsonParseNode(JsonDocument.Parse(uploadSessionStream).RootElement);
             return uploadSessionJsonNode.GetObjectValue(UploadSession.CreateFromDiscriminatorValue);
         }