Fix for C4267 warning (#23610)
### Description
A recent
[commit](https://github.com/microsoft/onnxruntime/commit/1fce51b3b25b369f5e0486cf3223e5caa53e44bd)
is causing an OVEP warning in
[openvino_provider_factory.cc](https://github.com/microsoft/onnxruntime/blob/main/onnxruntime/core/providers/openvino/openvino_provider_factory.cc#L151).
This PR fixes the warning.
### Motivation and Context
Minor fix
