Merge pull request #2269 from alphagov/error-message-ethnic-groups-br…

…oken-link

Remove link to archived ethnic groups pattern

src/components/error-message/index.md.njk

@@ -126,7 +126,6 @@ Use template messages for common errors on:
 - [character count](/components/character-count/#error-messages)
 - [checkboxes](/components/checkboxes/#error-messages)
 - [date input](/components/date-input/#error-messages)
-- [ethnic group](/patterns/ethnic-group/#error-messages)
 - [email address](/patterns/email-addresses/#error-messages)
 - [file upload](/components/file-upload/#error-messages)
 - [names](/patterns/names/#error-messages)