Use test_connection function for keepalive check

Replaces inline ping with existing test_connection function

apps/cistech-tunnel/shared/openconnect-vpn

@@ -521,11 +521,7 @@ start_watchdog() {
 
             # Keepalive ping every 5 minutes
             if [ $((now - last_keepalive)) -ge $keepalive_interval ]; then
-                if [[ -n "$IBMI_HOST" ]] && ping -c 1 -W 5 "$IBMI_HOST" &>/dev/null; then
-                    log DEBUG "Keepalive ping to $IBMI_HOST successful"
-                else
-                    log WARN "Keepalive ping to $IBMI_HOST failed (VPN may be degraded)"
-                fi
+                test_connection || log WARN "VPN may be degraded"
                 last_keepalive=$now
             fi
         else