This commit changes the code in such a way that the
"Start new conversation" button open the compose box with the channel
picker open, as we do when no channels is selected.
Fixes#28410.
Co-authored-by: Kunal Sharma <v.shm.kunal@gmail.com>
Forward message starts a new message with the quoted context
(message or selection).
The compose box opens with then channel picker open and no topic.
Also added documentation about this feature in the help center.
Fixes part 2 of #31953
Adds a message length limit indicator similar to the one in the compose box.
The tooltip message for the disabled save button now appears dynamically
based on whether the message exceeds the length limit or the editing time
has expired.
Fixes#25271.
Refactors `check_overflow_text` and `validate_message_length` functions.
This commit ensures that there won't be any change in the existing UI
of the compose box with the refactoring of the above functions.
