Indicate Notification Received when Chat Room is Out of View

[SethFalco]

Is your suggestion related to a problem? Please describe.
When a user is in a lot of chat rooms, a message / notification can occur in a room that's not scrolled into view.
As someone that does not depend on any kind of audio cue, when I received a message sometimes I don't notice at all that I got a new message.

Despite having an unread message, there is no visual guide of this because the "People" section isn't scrolled into view.

In this example, I sent a message and then deleted it. Deleting the message removes the (1) on the "People" section, however the chat room above still had activity and displays a white dot which I'd like to be aware of.

Describe the solution you'd like
There should be some kind of visual indicator that a message was received in the UI as well. For example Discord handles this situation quite well.

When a user is scrolled down so a new message is out of view, a little "NEW" badge appears to indicate there's a new message to see if one scrolls up.

Describe alternatives you've considered
Alternatively, the "People" field could be made sticky so that it always remains in view at the top.

Clicking it would scroll the user up to the top of the "People" section, and provides a visual cue that there is a new message.

[t3chguy]

There is stickiness already but it is limited to one header at each end.

Duplicate of #14057