[Fix] Prevent access on destroyed owner

[jembezmamy]

We've got some cases when Ember App is destroyed, but React component still tries to access an Ember service. This results in an error:

Error: Cannot call `.lookup('service:organization-manager')` after the owner has been destroyed
    at Container.lookup (http://localhost:7357/assets/vendor.js:575:15)
    at ApplicationInstance.lookup (http://localhost:7357/assets/vendor.js:10272:33)
    at useEmberService (http://localhost:7357/assets/chunk.b17651e957f6f92a7c28.js:6328:16)
    at useOrganizationManager (http://localhost:7357/assets/chunk.20e8505b24b143d532a8.js:6423:101)
    at useFetchForwardingEmail (http://localhost:7357/assets/chunk.20edc446a6268cec6b84.js:14706:105)
    at CopyEmailButton (http://localhost:7357/assets/chunk.20edc446a6268cec6b84.js:333:125)
    at renderWithHooks (http://localhost:7357/assets/chunk.b17651e957f6f92a7c28.js:97930:157)
    at updateFunctionComponent (http://localhost:7357/assets/chunk.b17651e957f6f92a7c28.js:98502:388)
    at beginWork (http://localhost:7357/assets/chunk.b17651e957f6f92a7c28.js:98910:549)
    at beginWork$1 (http://localhost:7357/assets/chunk.b17651e957f6f92a7c28.js:99966:93)

To prevent that, we should remove all Application Context children once the owner is destroyed.

[uanjoze]

🙏

[jembezmamy]

This approach is useful for debugging, it allows us to identify which component was not unmounted correctly. It might be useful in the future, but since the original issue is already fixed, let's close this PR.