remove options from method `createForm`

When calling `$flow->createForm($options)` in an action to create the form for the current (or next) step, these options will be passed to `createFormForStep` and the form will be created as expected. However, when applying saved data from previous steps, intermediate forms for those steps are created without passing these options to them, which may result in a differently built form.

To avoid WTFs caused by this behavior, it's cleaner to just remove the `$options` argument from `createForm` altogether and rely on `getFormOptions` entirely.