Fix nuget pipeline (#17110)

Fix nuget pipeline by correcting the calling convention on c# delegate.

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Co-authored-by: Randy Shuai <rashuai@microsoft.com>

csharp/src/Microsoft.ML.OnnxRuntime/InferenceSession.shared.cs

@@ -1060,6 +1060,7 @@ namespace Microsoft.ML.OnnxRuntime
             }
         }
 
+        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
         private delegate void OrtCallbackDelegate(IntPtr userData, IntPtr[] outputs, uint numOutputs, IntPtr status);
 
         private static OrtCallbackDelegate ortCallback = new OrtCallbackDelegate(OrtCallback);