Check consistency of configuration file at saving

[morray]

Describe the issue you are experiencing

At the moment the correctness of the config is only checked after start up. It would be be better to check during the save process to avaoid bringing the network into a undefined state

What type of installation are you running?

Home Assistant OS

Which operating system are you running on?

Home Assistant Operating System

Which add-on are you reporting an issue with?

DHCP Server

What is the version of the add-on?

1.3.0

Steps to reproduce the issue

1. create inconsistent setup file for the dhcp config
2. save
3. restart dhcp
   ...

System Health information

not needed

Anything in the Supervisor logs that might be useful for us?

No response

Anything in the add-on logs that might be useful for us?

No response

Additional information

No response

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.