InAppBrowser on .show() undefined and instance is vanished from the scope when passed from page to page?

# Bug Report

## Problem
Ok question may sound weird. **(you can also reproduce this by following below)**

I have 2 pages in my ionic 5 app.
page A has a login screen, call its .service.ts file as a.service.ts
page B has the Camera Preview plugin installed
a.service.ts has a method to pass InAppBrowser instance to page B from page A. ( so I can add hook of postMessage)
When inappbrowser instance is passed successfully to a.service.ts from A and to B as well.

Looks like below

inside a.service.ts

setIABPosstMessageHook(iab) {
this.iabInstance = iab; // set iab passed from page A here
this.router.navigateByUrl('camera-rdc'); // navigated to page success
this.cameraRdcController.getIABFromSender(this.iabInstance); // check below for method
}

inside B (camera controller)

getIABFromSender(iabInstance) {
iabInstance.on('message').subscribe((callbackData) => {
iabInstance.hide(); // hidie inappbrowser works
this.iab = iabInstance // iab set successfully to global variable this.iab
this.cameraTriggeredInIAB(callbackData.data.cameraSide); //starts camera
});
}

now on camera page, I have a close button which calls below method -

exitCameraView() {
this.cameraPreview.stopCamera().then(() => { //stop cammera
this.screenOrientation.unlock(); // unlock landscape orientation
this.iab.show(); // ERROR COMES HERE AS show on undefined!!!! how?
});
}

in debug mode, I see that its there in 'this' but after I click close button, somehow this iab is gone from this!! I can't seem to find how does this object got vanished.

because of that, my IAB is not showing up again. Help, please. I haven't faced any such issue in the angular or ionic side till today, but now I don't have any clue. Thanks.

### What is expected to happen?

show should work, but iab object is gone

### What does actually happen?

error as show on undefined

## Information
check above

### Environment, Platform, Device
latest ionic 5, testing on pixel 2 xl

### Version information

## Checklist

- [ x] I searched for existing GitHub issues
- [ x] I updated all Cordova tooling to most recent version
- [ x ] I included all the necessary information above

Start with the setIABPosstMessageHook, getIABFromSender, and exitCameraView entry points described in the report, and trace the InAppBrowser instance across navigation from page A to page B. Done means the instance remains available after the camera stops and iab.show() works from the close action.

Written by the indexing model from the issue text.