LIMS-1466: Disable dispatch form validation when using the shipping service

[ndg63276]

JIRA ticket: LIMS-1466

Summary:

The dispatch request form has quite strict validation, but little of it is used (or even displayed) if the shipping service will be used. This has led to problems where a hidden field fails validation and the user doesn't know how to fix the problem. We should disable validation if the shipping service is going to be used.

Changes:

• Move validation patterns out of model file and into functions within view file
• Tidy some whitespace

To test:

• Enable $use_shipping_service and $use_shipping_service_redirect in config
• Go to a test shipment (eg /shipments/sid/63609) and click "Dispatch"
• Change the country to eg Aruba to show the full form
• Add illegal characters to each field, check that they go red and display an error
• Change the country to United Kingdom, the fields should now be hidden. Check you can Proceed to the shipping service.