feat: the ChannelList components do not display information about received messages in threads

[MartinCupela]

Motivation As a user I would like to know that I have received a (important) message in a given channel's thread.

Acceptance Criteria

1. Register event listener for notifications about new messages arriving to thread
2. The ChannelPreview representing the channel, which received the reply should visually reflect the event
3. Send mark-read request only upon opening the thread (thread should be scrolled to the bottom automatically)