App Layout: Show all unread chats in "Unreads"

### Your use case

#### What would you like to do?
After a busy day when I did not open Element at all or not that often but have a few quiet minutes in the evening I would like to be able to catch up on everything that I did not see throughout the day.

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

Almost all of my rooms (in contrary to DMs) are muted, not because I do not want to read their messages but because I do not want to get distracted by them when I am not actively opening Element. It would be easier to read all the messages when I am not busy at the moment.

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

Use the "Unreads" filter tab of the new app layout to go through all of my unread messages. Right now muted chats are not displayed here but I could especially make use of this filter for muted chats. Since I get notifications for unmuted chats I usually read their messages quickly after they arrive and the "Unreads" tab stays empty.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

### Are you willing to provide a PR?

No