Delete route from system only if added by the client

[mlsmaycon]

This adds a flags to check if the addVPNRoute executed without issues before removing a route from the system

Describe your changes

Issue ticket number and link

Checklist

• [ ] Is it a bug fix
• [ ] Is a typo/documentation fix
• [ ] Is a feature enhancement
• [ ] It is a refactor
• [ ] Created tests that fail without the change (if possible)
• [ ] Extended the README / documentation, if necessary

[lixmal]

This is most likely superseded by changes in https://github.com/netbirdio/netbird/pull/1943, but needs tests

[mlsmaycon]

This is most likely superseded by changes in #1943, but needs tests

Ok, let's close this one, as it would need a better approach anyway.