Display API errors to the user

[cecilia-donnelly]

Now that the API returns human-readable errors if the data submitted was incorrect (e.g. birthday in the future), we should display those errors to the user of this client. Currently if the save fails the user doesn't get any notification -- the app just redirects back to the Search page.

[cecilia-donnelly]

See 581e4d2.

[cecilia-donnelly]

While the API errors are technically readable by a human, they're not really friendly enough for the client app. Instead of "A parameter value was invalid.: SSN must match the pattern ^[0-9xX]{9}$," for example, we should say something like, "This SSN has the wrong number of characters" or "Don't include - in SSNs."