correct issue where script is always run once

add capture of configure_modem.sh exit code and increment i if configure_modem.sh fails

src/ppp_connection_manager.sh

@@ -4,10 +4,12 @@ source functions.sh
 
 for i in {1..4}; do
     bash configure_modem.sh
+    MODEM_CONFIG=$?
     
     if [[ $MODEM_CONFIG -eq 0 ]]; then
         break
     fi
+    i=$(($i+1))
     sleep 1
 done