Separate toasts for existing & new device verification

Separate device verification toasts into ones for devices that were
there when the app loaded and a separate toast for each device that
has appeared since.

Reverts part of https://github.com/matrix-org/matrix-react-sdk/pull/4506
(clicking a device from your own UserInfo now triggers the legacy
verification flow again).

Fixes https://github.com/vector-im/riot-web/issues/13422
Fixes https://github.com/vector-im/riot-web/issues/13418

src/components/views/rooms/MemberInfo.js

@@ -160,13 +160,10 @@ export default createReactClass({
             // no need to re-download the whole thing; just update our copy of
             // the list.
 
-            // Promise.resolve to handle transition from static result to promise; can be removed
-            // in future
-            Promise.resolve(this.context.getStoredDevicesForUser(userId)).then((devices) => {
-                this.setState({
-                    devices: devices,
-                    e2eStatus: this._getE2EStatus(devices),
-                });
+            const devices = this.context.getStoredDevicesForUser(userId);
+            this.setState({
+                devices: devices,
+                e2eStatus: this._getE2EStatus(devices),
             });
         }
     },