Fix a number of minor code quality issues

Most of these are complaints from my IDE. Discovered by going through nearly every file looking for React warnings.

src/components/views/rooms/RoomRecoveryReminder.js

@@ -61,7 +61,6 @@ export default class RoomRecoveryReminder extends React.PureComponent {
                 loading: false,
                 error: e,
             });
-            return;
         }
     }