Bug Fix - C# API order incompatibile with C API (#13191)

### Description
Training C# bindings (ReleaseTrainingSession and ReleaseCheckpointState)
broke after an API order change in Training C API. This PR fixes this
issue.



### Motivation and Context
Bug Fix for Training C# bindings
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->

csharp/src/Microsoft.ML.OnnxRuntime/Training/NativeTrainingMethods.shared.cs

@@ -7,6 +7,7 @@
 namespace Microsoft.ML.OnnxRuntime
 {
 #if __ENABLE_TRAINING_ON_DEVICE__
+        // NOTE: The order of the APIs in this struct should match exactly that in
         // OrtTrainingApi  (onnxruntime_training_c_api.cc)
         [StructLayout(LayoutKind.Sequential)]
         public struct OrtTrainingApi
@@ -26,6 +27,9 @@ public struct OrtTrainingApi
             public IntPtr OptimizerStep;
             public IntPtr RegisterLinearLRScheduler;
             public IntPtr SchedulerStep;
+            public IntPtr GetParametersSize;
+            public IntPtr CopyParametersToBuffer;
+            public IntPtr CopyBufferToParameters;
             public IntPtr ReleaseTrainingSession;
             public IntPtr ReleaseCheckpointState;
         }

orttraining/orttraining/training_api/onnxruntime_training_c_api.cc

@@ -312,7 +312,7 @@ ORT_API_STATUS_IMPL(OrtTrainingApis::CopyParametersToBuffer, _Inout_ OrtTraining
   }
   auto session = reinterpret_cast<onnxruntime::training::api::TrainingSession*>(sess);
   ORT_API_RETURN_IF_STATUS_NOT_OK(session->CopyParametersToBuffer(*parameters_buffer, trainable_only));
-  
+
   return nullptr;
   API_IMPL_END
 }
@@ -339,6 +339,9 @@ ORT_API(void, OrtTrainingApis::ReleaseCheckpointState, _Frees_ptr_opt_ OrtCheckp
 }
 
 static constexpr OrtTrainingApi ort_training_api = {
+    // NOTE: The C# bindings depend on the API order within this struct. Since Training APIs are not officially
+    // released, it is OK to change the order here, however a corresponding matching change should also be done in the
+    // "OrtTrainingApi" struct in NativeTrainingMethods.shared.cs
     &OrtTrainingApis::LoadCheckpoint,
     &OrtTrainingApis::SaveCheckpoint,
     &OrtTrainingApis::CreateTrainingSession,