remove methods arg to requestVerification(DM)

as it's easy to have this argument be out of sync from all
the places this is called from the js-sdk. There is also little point,
as you can already specify the methods a consumer of the js-sdk
wants to provide through the verificationMethods option when creating
the client object.

src/components/views/dialogs/DeviceVerifyDialog.js

@@ -123,7 +123,7 @@ export default class DeviceVerifyDialog extends React.Component {
                 const roomId = await ensureDMExistsAndOpen(this.props.userId);
                 // throws upon cancellation before having started
                 const request = await client.requestVerificationDM(
-                    this.props.userId, roomId, [verificationMethods.SAS],
+                    this.props.userId, roomId,
                 );
                 await request.waitFor(r => r.ready || r.started);
                 if (request.ready) {