We currently don't have a nice UI to show unread messages for the thread,
and it will take some time to create one. For now, this commit makes it so
new messages inside a thread do not count towards a chat channel's unread
counts, and new messages sent in a thread do not update a user's `last_read_message_id`
for a channel.
In addition, this PR refactors the `Chat::ChannelFetcher` to use the `Chat::ChannelUnreadsQuery`
query class for consistency, and made said class able to return zeroed-out records
for channels the user is not a member of.
Finally, a small bug is fixed here where if a user's `last_read_message_id` for
a channel was a thread's OM ID, then the thread OM would not show in the
main channel stream for them until another reply to the channel was posted.
This commit introduces a new thread indicator for channels with `threading_enabled`
set to true and the `enable_exp` site setting set to true. In addition, in the main channel
stream we now hide all messages that are linked to threads except for the original message,
disabling the concept of an "echo mode" for now, we may revisit this in future. We also
remove the jigsaw puzzle "Open Thread" button for message actions, since the thread
indicator can just be used instead.
This also stops the `Chat::Publisher` from sending any messages related to chat
messages that are linked to a thread, unless that chat message is the OM of the
thread. A subsequent PR will link up all MessageBus events within the thread panel,
and for the message indicators.
Another subsequent PR will add the excerpt of the latest message in each thread,
as well as the avatars of the users messaging in the thread.
Co-authored-by: Joffrey JAFFEUX <j.jaffeux@gmail.com>