For #20919 quit the app after removing a study.

[Amejia481]

The crash on #20919 was caused because the deleted experiment changed UI according with experiment details, but as we removed the experiment the UI was still there, causing an inconsistent state, as some part of the code know that were are not on a experiment but some part that were not reloaded still have the experiment UI, to avoid similar inconsistencies and be safe let's just quite the app and allow to everything start fresh.

java.lang.ClassCastException
	at org.mozilla.fenix.settings.SettingsFragment.updateMakeDefaultBrowserPreference(SettingsFragment.kt:500)
	at org.mozilla.fenix.settings.SettingsFragment.update(SettingsFragment.kt:230)
	at org.mozilla.fenix.settings.SettingsFragment.onResume(SettingsFragment.kt:174)
	at androidx.fragment.app.Fragment.performResume(Fragment.java:3039)
	at androidx.fragment.app.FragmentStateManager.resume(FragmentStateManager.java:607)
	at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:306)
	at androidx.fragment.app.SpecialEffectsController$FragmentStateManagerOperation.complete(SpecialEffectsController.java:742)
	at androidx.fragment.app.SpecialEffectsController$Operation.completeSpecialEffect(SpecialEffectsController.java:669)
	at androidx.fragment.app.DefaultSpecialEffectsController$SpecialEffectsInfo.completeSpecialEffect(DefaultSpecialEffectsController.java:779)
	at androidx.fragment.app.DefaultSpecialEffectsController.startAnimations(DefaultSpecialEffectsController.java:239)
	at androidx.fragment.app.DefaultSpecialEffectsController.executeOperations(DefaultSpecialEffectsController.java:119)
	at androidx.fragment.app.SpecialEffectsController.executePendingOperations(SpecialEffectsController.java:294)
	at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2202)
	at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2106)
	at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
	at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524)
	at android.os.Handler.handleCallback(Handler.java:883)
	at android.os.Handler.dispatchMessage(Handler.java:100)
	at android.os.Looper.loop(Looper.java:214)
	at android.app.ActivityThread.main(ActivityThread.java:7682)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)

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- [ ] **Tests**: This PR includes thorough tests or an explanation of why it does not
- [ ] **Screenshots**: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not
- [ ] **Accessibility**: The code in this PR follows [accessibility best practices](https://github.com/mozilla-mobile/shared-docs/blob/master/android/accessibility_guide.md) or does not include any user facing features. In addition, it includes a screenshot of a successful [accessibility scan](https://play.google.com/store/apps/details?id=com.google.android.apps.accessibility.auditor&hl=en_US) to ensure no new defects are added to the product.

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[Amejia481]

@Mergifyio backport releases_v92.0.0

[mergify]

Command backport releases_v92.0.0: success

Backports have been created

• #20943 For #20919 quit the app after removing a study. (backport #20933) has been created for branch releases_v92.0.0