Form field validation: update copy to be more specific on the problem

[angela-tran]

Acceptance Criteria

• Configure the browser validation message - https://developer.mozilla.org/en-US/docs/Web/HTML/Constraint_validation#controlling_the_text_of_constraint_violation
• Test with different browser locales
• Add custom copy for both Eligibility Index (radio buttons) and Eligibility Confirm (text fields)

[indexing]

@angela-tran As discussed in our weekly stand-up, here is the single field validation message for the agency card number field.

Please enter a 4-digit number.

Field validation is initiated when the user clicks the Find my record button. This error will display when….

• The user provides no value in the card number field.
• When the user provides a number in the card number field, but that number is less than or greater than the required number of digits
• When the user provides a value in the card number field, but that value that includes characters other than numbers.

I don't believe we are accounting for the last scenario in the current scope, but this is the error message the app currently displays.

cc// @srhhnry @thekaveman