New Room List: Introduce a compact mode

### Your use case

#### What would you like to do?

I would like an option to reduce the vertical height of each item in the new room list.

Compare this to Discord's default (non-compact) channel/room UI density (which does lack avatars):


Discord has a compact mode for their channel list, which reduces the margins around "# general":


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

Each item has some vertical padding, and it'd be nice to have a mode where that could be eliminated for more visual density.

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

Remove the vertical padding around the avatar/room name through use of a new option.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_