App gets stuck on instantiation after switching party

[bjosttveit]

Description of the bug

If you instantiate an app, then go back to party selection and select a different party, you will see an infinite loader with reason='instantiating'. The reason is the following check:

const shouldCreateInstance = !!party && !instantiation.lastResult && !instantiation.isLoading;

This check fails due to instantiation.lastResult being truthy, probably because we already created an instance with a different party before.

It may also be prevented by the implementation of the instantiate function:

if (instantiate.data || instantiate.isPending || instantiate.error || isInstantiatingRef.current) {
  return;
}

Steps To Reproduce

1. Go to https://ttd.apps.tt02.altinn.no/ttd/frontend-test
2. Login with a testid with at least two parties
3. Select 1st party, and create a new instance
4. Navigate to /#/party-selection and select a different party
5. See infinite loading screen

Additional Information

No response