remove sign-up button for extauth also on the RequireAuthentication card

Author: Ithanil

app/javascript/components/rooms/room/join/RequireAuthentication.jsx

@@ -36,7 +36,6 @@ export default function RequireAuthentication({ path }) {
           env?.EXTERNAL_AUTH ? (
             <Form action={process.env.OMNIAUTH_PATH} method="POST" data-turbo="false">
               <input type="hidden" name="authenticity_token" value={document.querySelector('meta[name="csrf-token"]').content} />
-              <Button variant="brand-outline-color" className="btn btn-lg m-2" type="submit">{t('authentication.sign_up')}</Button>
               <Button variant="brand" className="btn btn-lg m-2" type="submit">{t('authentication.sign_in')}</Button>
             </Form>
           ) : (