Revert egov.uscis.gov site quirk.

Site has changed, hence the 'required=no' workaround no longer needed.

R=
BUG=154611

Review URL: https://codereview.chromium.org/141713006

git-svn-id: svn://svn.chromium.org/blink/trunk@166275 bbb929c8-8fbe-4397-9dbb-9b2b20218538