* Add client side postcode validation
* Prevent server-side validation
* Adjust translation
* Only validate postcode if country is available
* Specify return type of isPostcode()
* Convert function to static variable set
* Refactor <ValidatedTextInput> for postcode validation
* Refactor customValidationHandler
* Use customValidationHandler as intermediate function
* Hyphenate file names
* Update packages/checkout/utils/validation/is-postcode.ts
Co-authored-by: Mike Jolley <mike.jolley@me.com>
* Normalise postcode on input
* Fix usage of out of date value from input field
---------
Co-authored-by: Mike Jolley <mike.jolley@me.com>
* Custom validation strings using a new function named getValidityMessageForInput
* getValidityMessageForInput tests
* Added integration test for error message
* Clear value
* update test strings