Allow sticker widget on element web/desktop to be resized

### Your use case

#### What would you like to do?

I'd like to enlarge the sticker widget on element.

#### Why would you like to do it?

Because the widget is smaller than I like.

#### How would you like to achieve it?

Ideally, there'd be a special mouse when you hover the edge of the widget, allowing you to easily enlarge the widget by dragging one of the edges. Just like you'd do with windows on floating window managers like KDE or Cinnamon.

### Have you considered any alternatives?

I can't think of any other way to fix a too small widget than to make it larger.

### Additional context

I'm using a custom sticker widget (https://github.com/maunium/stickerpicker/wiki/Enabling-the-widget) but this should just as much apply to the one that comes with element by default.