Fix room list treeview filtering not ignoring modifier keys

src/components/structures/LeftPanel.tsx

@@ -306,6 +306,7 @@ export default class LeftPanel extends React.Component<IProps, IState> {
     };
 
     private onRoomListKeydown = (ev: React.KeyboardEvent) => {
+        if (ev.altKey || ev.ctrlKey || ev.metaKey) return;
         // we cannot handle Space as that is an activation key for all focusable elements in this widget
         if (ev.key.length === 1) {
             ev.preventDefault();