[DML EP] Add missing member initializer DmlGraphNodeCreateInfo::nodeC…

…ount (#17505)

### Description
<!-- Describe your changes. -->

This adds a missing member initialization.

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

It caused an access violation in
`Dml::GraphDescBuilder::BuildGraphDesc`.

onnxruntime/core/providers/dml/DmlExecutionProvider/inc/IWinmlExecutionProvider.h

@@ -80,7 +80,7 @@ namespace Windows::AI::MachineLearning::Adapter
     // Either nodesAsOperatorDesc or nodesAsIDMLOperator can have non-zero size.
     struct DmlGraphNodeCreateInfo
     {
-        uint32_t nodeCount;
+        uint32_t nodeCount = 0;
         std::vector<std::unique_ptr<AbstractOperatorDesc>> nodesAsOperatorDesc;
         std::vector<Microsoft::WRL::ComPtr<IDMLOperator>> nodesAsIDMLOperator;
         std::vector<DML_INPUT_GRAPH_EDGE_DESC> inputEdges;