We pass user_settings object to all_notifications and
get_notifications_table_row_data such that we can use these
functions for realm-level settings also.
The only caller for this function was settings_config,
so we put it there.
For the stream_edit test we no longer mock the function.
(The reason we mocked the function was more about avoiding
the heavy settings_notifications import than the function
itself.) This gives some incidental coverage, but then I
also add some more real coverage on it.
Sahil Batra
Anders Kaseorg
Priyank Patel
Steve Howell