Make codemodel same in converter and codegen

[pshao25]

Currently, openapi-to-typespec will leverage C# codegen to generate resource hierarchy, and then map the resource generated from C# codegen to the codemodel generated from openapi-to-typespec. However, these two have different config for M4, therefore the codemodel generated from openapi-to-typespec is different from that of C# codegen. We should make them same.