fix/error removing handlers when SDK is not initialized

[Ribas187]

Description

Fix for the "initWithContext" error while trying to remove handlers when the SDK is not initialized

Details

Motivation

This issue happens in Android specifically when the app is closed and the OneSignal SDK has not been initialized yet
The error accused in the log is this one "Must call 'initWithContext' before use", and can be seen in the opened issue [Bug]: initWithContext error in android-1554

Scope

The mentioned code is inside the removeHandlers() method which is called inside onHostDestroy() and onCatalystInstanceDestroy() and causes a crash when the SDK has not been initialized before.
This PR adds one verification to check whether the initialization is made with the value oneSignalInitDone

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.

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This change is 

[Ribas187]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @Ribas187)

[jpangan]

Hello guys. What's the status of this? it seems like everyone is facing the same issue.

[Ribas187]

Hello guys. What's the status of this? it seems like everyone is facing the same issue.

Hey @jpangan I need approval from @nan-li or @jennantilla on this one. I faced the same issue in my company, but while we wait for the new version, we did a workaround by applying this change using a patch in the node_module package

[nan-li]

Thank you @Ribas187 for submitting and testing this PR!

[Romick2005]

Looks good!