Open/Close Submenu With Click

### Your use case

> This was refused by the Design team https://github.com/element-hq/element-web/pull/34468#issuecomment-5281307610
> > Based on the issue you cited: No, it was not refused. This is a different request.

Room list > 'More Options' > Hover over 'Move to' > Remove hover > Submenu persists

The submenu is opened by hovering - not a click. So having it persist outside hover is unexpected. There is also no click to close the submenu alone, once it's opened you can't close it without closing the entire menu.

#### What would you like to do?
Click to open/close submenu.
#### Why would you like to do it?
For consistent and familiar interaction model.
#### How would you like to achieve it?
Open the submenu when its parent item is clicked, and close it when clicked again. Clicking outside the submenu should continue to close the entire menu.

### Have you considered any alternatives?

#### Removing cursor/hover dismisses submenu
Dismiss the submenu when the cursor is moved away from it and its parent menu item, while keeping the main menu open.

### Additional context

https://github.com/element-hq/element-web/issues/34769#issuecomment-5395991608