We show `realm_empty_topic_display_name` for empty string topics
in the recent conversations view.
This commit makes it possible for users to search for
the `realm_empty_topic_display_name` value to filter out empty
string topics.
We update max_avatars on rerenders based on recent view width
to prevent participant avatars from overflowing their width.
We use resize event to update `--recent-view-max-avatars` which
is checked on `complete_rerender`.
This commit adds support to display `realm_empty_topic_display_name`
value in the recent conversations view for topics having the actual
value of empty string.
This commit is a part of the efforts to rename btn-related classes
and variables to align with Zulip's no-abbreviations policy and
streamline the search results.
