skip quantized model C# tests on GPU (#13782)
### Description
Skip quantized model C# tests on GPU too.
### Motivation and Context
It looks the current test result isn't reasonable.
https://github.com/onnx/models/issues/581
Once we update the image, the quantized model [test data will be
generated with
VNNI](https://github.com/onnx/models/commit/ba629906dd91872def671e70177c5544e0ea9e02),
the CI would be broken.
