Do full registration if HS doesn't support ILAG

ILAG only works on HSes that allow registering without an email
address, so whenever we redirect to the ILAG flow, check what
registration flows the server supports, and if it doesn't offer one
that's ILAG-compatible, prompt the user to go through the full
registration process instead.

This doesn't change all the entry points into ILAG, I'll do that
in a separate commit.

src/components/structures/MatrixChat.js

@@ -45,6 +45,7 @@ import createRoom from "../../createRoom";
 import KeyRequestHandler from '../../KeyRequestHandler';
 import { _t, getCurrentLanguage } from '../../languageHandler';
 import SettingsStore, {SettingLevel} from "../../settings/SettingsStore";
+import { startAnyRegistrationFlow } from "../../Registration.js";
 
 /** constants for MatrixChat.state.view */
 const VIEWS = {
@@ -471,7 +472,7 @@ export default React.createClass({
                 action: 'do_after_sync_prepared',
                 deferred_action: payload,
             });
-            dis.dispatch({action: 'view_set_mxid'});
+            dis.dispatch({action: 'require_registration'});
             return;
         }
 
@@ -479,7 +480,11 @@ export default React.createClass({
             case 'logout':
                 Lifecycle.logout();
                 break;
+            case 'require_registration':
+                startAnyRegistrationFlow(payload);
+                break;
             case 'start_registration':
+                // This starts the full registration flow
                 this._startRegistration(payload.params || {});
                 break;
             case 'start_login':
@@ -945,7 +950,7 @@ export default React.createClass({
                 });
             }
             dis.dispatch({
-                action: 'view_set_mxid',
+                action: 'require_registration',
                 // If the set_mxid dialog is cancelled, view /home because if the browser
                 // was pointing at /user/@someone:domain?action=chat, the URL needs to be
                 // reset so that they can revisit /user/.. // (and trigger