sink.text.details: replace switch to convert status with cast

sink.text.details: replace switch to convert status with cast

Replace the switch currently used in details_consume, to convert the
status of bt_message_iterator_next, with a simple cast, as per standard
procedure.

Change-Id: Iea35bd26f4af983d7cca37fc01b2b2f903cc73da
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/3394
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>