New Issue Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.
• I can reproduce the issue with the latest version of Parse Server.

Issue Description

Calling user.linkWith() server-side doesn't remove the "anonymous" field from the authData object field, causing Parse.AnonymousUtils to still report the user as an Anonymous user.

Steps to reproduce

Parse.Cloud.define('linkWithAccount', async (request) => { const user = request.user; if (!user) throw 'NoUser'; const provider = request.params.provider as string; const authData = request.params.authData as any; if (!provider) throw 'NoProvider'; else if (!authData) throw 'NoAuthData'; await user.linkWith(provider, { authData }, { useMasterKey: true, sessionToken: user.getSessionToken() }); return { ok: true }; });

Actual Outcome

The authData field on Parse Database still has the "anonymous" field, resulting in Parse.AnonymousUtils to still report the user as an Anonymous user

{ "anonymous": { "id": "<random-string>" }, "<linked_service_name>": { ...linked_service_data } } 

Expected Outcome

Inpecting the authData field on Parse Database not have the anonymous field (should only have..)

{ "<linked_service_name>": { ...linked_service_data } } 

Failing Test Case / Pull Request

• 🤩 I submitted a PR with a fix and a test case.
• 🧐 I submitted a PR with a failing test case.

Environment

Server

• Parse Server version: 4.5.0
• Operating system: Mac OS X Mojave 10.14.6
• Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc): Heroku

Database

• System (MongoDB or Postgres): MongoDB
• Database version: FILL_THIS_OUT
• Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc): MongoDB Atlas

Client

• SDK (iOS, Android, JavaScript, PHP, Unity, etc): Javascript (React-Native)
• SDK version: 2.19.0

Logs