Convert EmailFields to GovukEmailFields

Changes those fields (and sometimes also regular text input fields)
 in the following forms:
- LoginForm
- RegisterUserForm
- ChangeEmailForm
- FeedbackOrProblem
- AcceptAgreementForm
- ChangeNameForm (only name field here, but used in the same template
field as ChangeEmailForm here: app/templates/views/user-profile/change.html)

Also includes changes to templates that use this form
and associated tests.

app/templates/views/service-settings/email-reply-to/_verify-updates.html

@@ -1,5 +1,4 @@
 {% from "components/banner.html" import banner, banner_wrapper %}
-{% from "components/textbox.html" import textbox %}
 {% from "components/page-footer.html" import page_footer %}
 {% from "components/form.html" import form_wrapper %}
 {% from "components/button/macro.njk" import govukButton %}
@@ -47,11 +46,12 @@
     {% call form_wrapper(
       action = form_url
     ) %}
-      {{ textbox(
-        form.email_address,
-        width='1-1',
-        safe_error_message=True,
-        hint='This should be a shared inbox managed by your team, not your own email address'
+      {{ form.email_address(
+          param_extensions={
+            "hint": {"text": "This should be a shared inbox managed by your team, not your own email address"},
+            "classes": "govuk-!-width-full"
+          },
+          error_message_with_html=True
       ) }}
       {% if not first_email_address and not existing_is_default %}
         {{ form.is_default }}