Parse.Query: can't use authData query-parameter in User-query #4580

Issue Description

Can't use authData as Query-Parameter

Steps to reproduce

1. Authenticate via an Authentication Adapter so authData is added to the User object.
2. Run a Query (with masterkey enabled) like GET API_BACKEND/classes/_User?where={"authData":{"$exists": true}}

Expected Results

Query Result should contain all Users with non empty authData fields

Actual Outcome

Query Result is empty

Environment Setup

• Server
  • parse-server version (Be specific! Don't say 'latest'.) : 2.4.2
  • Operating System: ubuntu 16.10
  • Hardware: VM
  • Localhost or remote server? (AWS, Heroku, Azure, Digital Ocean, etc): local