replace card submission error dispatches with a processing result

[kumar303]

There is strange action we dispatch called CARD_SUBMISSION_ERRORS. It's odd because it's tightly coupled to the card form entry and that creates complications like this in actions/subscriptions.js:

fetch(...).fail($xhr => {
  ...
  if (allErrors && arrayHasSubString(allErrors, 'already subscribed')) {
    dispatch(notificationActions.showError({
      errorCode: errorCodes.ALREADY_SUBSCRIBED,
      ...
    }));
  } else if (data.pay_method_nonce) {
    dispatch({
      type: actionTypes.CREDIT_CARD_SUBMISSION_ERRORS,
      ...
    });
  }
});

This code has to make a decision whether to dispatch a credit card related error or just a general app error.

What really needs to happen is this: tell the form that initiated the form processing that an error occurred.

I think the processing state introduced by #421 is a good pattern for this. The code would need to be expanded and dispatches would probably look more like this:

fetch(...).fail($xhr => {
  dispatch(processingActions.stopProcessing(
    processingId, 
    {wasError: true, errorResult: $xhr.responseJSON}
  ));
});

The state reducer would need updating too and components will need to check for ongoing processing more like processingState[processingId] && processingState[processingId].inProgress.

With that, both the transaction subscribe component and any credit card entry component can receive the change in processing state by looking for processingState[processingId].errorResult.