Fixed IOTCELL-2384

Earlier we called AT+QICSGP only if the username and password was set.
It seems that we must call it also to set up APN while in AT mode.
This commit fixes the issue + updated IPv4/v6 handling to be correct in the same call

Author: Antti Kauppila

features/cellular/framework/targets/QUECTEL/BG96/QUECTEL_BG96_CellularContext.cpp

@@ -69,11 +69,20 @@ ControlPlane_netif *QUECTEL_BG96_CellularContext::get_cp_netif()
 
 nsapi_error_t QUECTEL_BG96_CellularContext::do_user_authentication()
 {
+    uint8_t type = 1;
+    if ((uint8_t)_pdp_type > 1) {
+        type = 2;
+    }
     if (_pwd && _uname) {
-        if (_at.at_cmd_discard("+QICSGP", "=", "%d%d%s%s%s%d", _cid, 1,
+        if (_at.at_cmd_discard("+QICSGP", "=", "%d%d%s%s%s%d", _cid, type,
                                _apn, _uname, _pwd, _authentication_type) != NSAPI_ERROR_OK) {
             return NSAPI_ERROR_AUTH_FAILURE;
         }
+    } else {
+        if (_at.at_cmd_discard("+QICSGP", "=", "%d%d%s", _cid, type,
+                               _apn) != NSAPI_ERROR_OK) {
+            return NSAPI_ERROR_AUTH_FAILURE;
+        }
     }
 
     return NSAPI_ERROR_OK;