Ability to view multiple screenshares at once

### Your use case

#### What would you like to do?
- Notice that more than one person is screensharing - The bars on the bottom left are the only indicators
- Switch between streams also with the mouse instead of only the arrow keys (I first thought its not possible until I later tried the arrow keys)
- See multiple streams at the same time

#### Why would you like to do it?
I'm often in calls with multiple persons and sometimes more than one is streaming

#### How would you like to achieve it?
- Add some buttons to change call layout
- Let the user decide to not watch a stream to avoid clutter (and bandwidth usage)
- element-hq/element-web#30342 this with stream

Thank you!

### Have you considered any alternatives?

_No response_

### Additional context

_No response_