ns: TC_sns_bss_change_weight_timeout rework TC to use g_handle_rx_alive

With g_handle_rx_alive the test case doesn't need to use alt{}
as f_ns_exp takes care of the NS_ALIVE.

Related: OS#5036
Change-Id: I45f4392b556912bf60859f354a5687a44e6beeb1
1 file changed