Fixes more instances of double-translation (#7259)

src/components/views/auth/RegistrationForm.tsx

@@ -21,7 +21,7 @@ import { MatrixClient } from 'matrix-js-sdk/src/client';
 import * as Email from '../../../email';
 import { looksValid as phoneNumberLooksValid } from '../../../phonenumber';
 import Modal from '../../../Modal';
-import { _t } from '../../../languageHandler';
+import { _t, _td } from '../../../languageHandler';
 import SdkConfig from '../../../SdkConfig';
 import { SAFE_LOCALPART_REGEX } from '../../../Registration';
 import withValidation, { IValidationResult } from '../elements/Validation';
@@ -431,8 +431,8 @@ export default class RegistrationForm extends React.PureComponent<IProps, IState
             return null;
         }
         const emailLabel = this.authStepIsRequired('m.login.email.identity') ?
-            _t("Email") :
-            _t("Email (optional)");
+            _td("Email") :
+            _td("Email (optional)");
         return <EmailField
             fieldRef={field => this[RegistrationField.Email] = field}
             label={emailLabel}