Merge pull request #879 from david-cermak/fix/modem_sim_napt

[modem_sim]: Enable LWIP-NAPT by default in modem simulator

Author: david-cermak

common_components/modem_sim/sdkconfig.defaults

@@ -75,3 +75,5 @@ CONFIG_AT_HTTP_COMMAND_SUPPORT=y
 CONFIG_AT_BLE_COMMAND_SUPPORT=n
 CONFIG_AT_BLE_HID_COMMAND_SUPPORT=n
 CONFIG_AT_BLUFI_COMMAND_SUPPORT=n
+CONFIG_LWIP_IP_FORWARD=y
+CONFIG_LWIP_IPV4_NAPT=y