[AVRCP1.6 CT] Add reply status to get_folder_items_callback.

It is useful to know what error code the get_folder_items_cmd gets back
with since it can help the UI decide if to keep fetching more. For ex.
if the return code is out of range then the UI does not need to keep
fetching anymore. This is useful for folders where we do not know the
size before hand (Media Player List or Now Playing List).

Bug: b/31253501

Change-Id: I0f43167d00bcf2e1e320be086fd9cacd163906a1
(cherry picked from commit e3a032a89ac2f20e96808fe2bded2c42fa3afb14)