OPENTHREAD_CONFIG_SRP_SERVER_PORT_SWITCH_ENABLE macro

@def OPENTHREAD_CONFIG_SRP_SERVER_PORT_SWITCH_ENABLE Define to 1 to enable SRP server feature to save its own port in non-volatile settings. When enabled, the SRP server will save its port in the non-volatile settings. On a server restart (e.g., due to a device reset) it will restore the port and change to a different one. The info is written to Settings after the first service has been registered due to receiving an SRP Update.