[Azure] Reindex API for azure fails during entitlement calls

The reindex api fails for azure during entitlements call.

Sample request:

POST https://osdu-dev.msft-osdu-test.org/api/indexer/v2/reindex { "kind": "opendes:at:wellbore:1.0.0" }

Response: { "timestamp": "2021-02-10T09:31:21.560+00:00", "status": 500, "error": "Internal Server Error", "message": "java.lang.String cannot be cast to com.microsoft.azure.spring.autoconfigure.aad.UserPrincipal", "path": "/api/indexer/v2/reindex" }

The error comes from getGroups() method of EntitlementsServiceAzure class

cc: @manishk , @njain5 , @nthakur , @komakkar