EdmHelpers GetClrType needs IServiceProvider

The EdmHelpers static class has a method GetClrType that takes IServiceProvider as an argument. Subsequently it pulls an IEdmModel from the container. IEdmModel should be a parameter on this function.

Part of https://github.com/OData/RESTier/issues/629.
See also https://github.com/jspuij/RESTier/issues/11.