Update validation to match server error.

When a using the forgottenRoute if you enter an incorrectly formatted
email address you would see the error message 'Invalid Email', however
if you entered an email address that was correctly formatted but missing
the error message would be 'Invalid email address'.

This fixes the discrepancy.
Merge pull request #3467 from rwjblue/update-validation-to-match-server-error

Update validation to match server error.