Debug the roles function using the local auth emulator

**Is your feature request related to a problem? Please describe.**
Enable local dev for [role management](https://docs.microsoft.com/azure/static-web-apps/authentication-authorization?tabs=function) through serverless functions

**Describe the solution you'd like**
Test programmatically assigned roles in local environment

**Describe alternatives you've considered**
Call the auth function locally with something like Postman to ensure it responds with the right roles given an input.
Use the local emulator to set custom roles at login to test how your app works with different roles.

**Additional context**
[Tutorial: Assign custom roles with a function and Microsoft Graph](https://docs.microsoft.com/azure/static-web-apps/assign-roles-microsoft-graph)