fix: oneshot rename `br-guest_turris` -> `br-guest-turris` in /etc/config/network on TOS 6.x
Prepare oneshot fix package that will rename br-guest_turris
-> br-guest-turris
in existing configuration.
Currently there can be two different, but valid, configurations for guest network bridge - for details, see turris/foris-controller/foris-controller#256 (closed).
Essentially, either configs should work fine, but it is confusing to have two possible valid configuration when debugging something in turris diagnostics. It would be nice to have just one supported configuration.
This will align existing network config after migration from TOS 5.x to 6.x with the value, that foris-controller expects.