Refactors get_recipient_label so that it's a bit clearer what the
recipient_information parameter is for and what we do when that
parameter is undefined.
In doing so, we no longer treat the constructed objects, that are
passed as the recipient_information parameter, and actual Message
objects, that we get from the current message list view, as the
same thing.
(cherry picked from commit 7d3b77e490)
Renames update_reply_recipient_label to
update_recipient_text_for_reply_button.
This better matches the function that sets the default text for
the closed compose box button: set_standard_text_for_reply_button.
(cherry picked from commit 94fe5fc173)
This commit unifies translation strings for reply button label
to reduce translation effort.
Both the `has_empty_string_topic` and other cases now use a single
"Message <z-recipient-label></z-recipient-label>"`, with dynamic
content passed appropriately.
This commit adds support to display `realm_empty_topic_display_name`
value as the compose reply button label for topics having the actual
value of empty string.
Since we allow calling `add_messages` without checking fetch status,
it can lead to non-contiguous message history due to latest message
being added to a message list without previous messages being
fetched.
To fix it, we only allow adding new messages via message_fetch
which properly sets `anchor` to the last message in the list
before fetching and adding messages to the list.
