formValidity
Description#
This store provides the overall form status when using custom form validations, provided in the formValidation options object. If none are provided this store will not update.
The store contains a Object that can contains the key of any validations that have failed, and a string value of the error message.
Every time there is a value update the store is reset and any custom validations called, they should return null for a valid result,
or a string for an invalid result, which can be used to display error messages.