Fix several issues:
1. Remove MyModel from beforeEach and request it on demand from the test. As the configuration
can change this instance will be obselete and it is error prone.
2. Replace catch for then to handle adverse success responses.
3. Move setupHttpTestRequestInterceptor to setTestAngularModuleConfig and ensure interceptor is not
added multiple times
4. Mark requests intercepted by HttpTestRequestInterceptor to improve error handling