Auto-reuse existing installation object when migrating from ObjC SDK #426

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 versions of Parse Server and the Parse Swift SDK.

Issue Description

After migrating an app to the Parse Swift SDK, launching the app will create a new _Installation object with a new installationId. It will appear as if the app had been uninstalled and then reinstalled, even though it only changed the Parse SDK. See migration guide/known issues.

An SDK change should not create a new installation, because it is not a new but existing installation. This bug also could make it difficult for developers to migrate from the Parse ObjC SDK, as data that is stored in the original installation object and any references to that installation object need to be migrated.

Steps to reproduce

n/a

Actual Outcome

A new installation object is created.

Expected Outcome

Any existing installation object should be used as the current installation.

Environment

Client

• Parse Swift SDK version: 4.14.2