Unexpected behavior on the `exists` method

Issue Description

An object exists in the database. You need a sessionToken to access it.

If you use the Parse.Object exists method without sessionToken instead of throwing an error, it resolves with the value false. I think it's quite an unexpected behavior. It's caused by theses lines of code

https://github.com/parse-community/Parse-SDK-JS/blob/f2d76805000488fefce2b0c2e73d8953007f2b1c/src/ParseObject.js#L972-L974

And comes from this discussion : https://github.com/parse-community/Parse-SDK-JS/pull/898#discussion_r316447203

Steps to reproduce

• Create an object in database with limited access
• Try Catch the exits method without any sessionToken

Expected Results

It should throw an error

Actual Outcome

It does not throw, it returns false as if the object do not exist

Test Case

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Environment Setup

• Server

  • parse-server version (Be specific! Don't say 'latest'.) : 4.1.0
  • Operating System: MacOS
  • Localhost or remote server? localhost

• JS SDK

  • JS SDK version: [FILL THIS OUT]
  • Application? (Browser, Node, React-Native, etc): [FILL THIS OUT]

Logs/Trace

Start at the linked ParseObject.js lines that implement the exists method, then review the integration tests under the Parse-SDK-JS integration/test directory. Reproduce the limited-access object case without a sessionToken and confirm that the completed behavior matches the issue's expected error handling.