skip 2 models in C# test (#13384)
### Description
<!-- Describe your changes. -->
### Motivation and Context
these 2 models are also skipped in gtest
https://github.com/microsoft/onnxruntime/blob/fc12abf6b1e66a3a09622210ef5d5c4574e070fe/onnxruntime/test/providers/cpu/model_tests.cc#L119-L122
