fix issues hidden by Unconfined Dispatcher

[gabrielittner]

This replaces the dispatcher used in tests with Dispatchers.Default. There was a combination of things at play here.

1. Initial state is now visible to all tests again, this was expected from me. I only removed those expects in StateFlow and CoroutineScope as constructor Parameter #130 because I had to use Unconfined
2. Any test that relied on a dispatched action for the first state change (OnActionTest and CustomIsInStateDslTest) was affected by an issue in FlowReduxStateMachine. Because of the launch that is done to start the store and it using MutableSharedFlow for incoming actions, any action that is dispatched before the launch body executes was lost. So the tests relying on an action didn't work. In real world use cases this is probably not an issue because you don't start dispatching actions a few millisecods later. I've changed the implementation to a Channel which will suspend the dispatch until we start collecting the actions.
3. The updated onEnter test was not set up for asynchronous events. expectNoEvents does not suspend or anything to wait that there are no more events, it just checks that there is nothing in it's queue. Because of the async dispatch of A1 the following assertEquals happens too early and the counter is still 0 because not even onEnter of S1 finished running yet. I've changed the test to use GenericState witch changing values so that we can wait for them with expectItem while still staying in the same state. The assertion that onEnter was only called once now happens after the test block when we know all invocations are done.

fixes #128, closes #171

[sockeqwe]

Looks good, still not sure why tests are failing

[gabrielittner]

Everything's green 🎉