FST: Remove WPA_ASSERT from wpas_fst_send_action_cb()

FST: Remove WPA_ASSERT from wpas_fst_send_action_cb()

It was possible to hit this WPA_ASSERT when FST-MANAGER SESSION_REMOVE
command is exececuted when in not-associated state. In
CONFIG_EAPOL_TEST=y builds, this would result in the wpa_supplicant
process being terminated. Convert this WPA_ASSERT to a check that does
not terminate the process, but only rejects the command if wpa_s->bssid
does not match the da argument.

Signed-off-by: Jouni Malinen <j@w1.fi>