Comment 5 for bug 2063331

Confirmed on a laptop (amd64) where I plugged some extra usb-to-ethernet adapters.

* To clarify: this happens when the user reboots to the installed system, not at install time. And is it not specific to riscv64 in any way.

* Interfaces marked as 'disabled' at install time get configured as 'dhcp4' on the installed system. The 'optinal' setting is not set, and it defaults to 'false'.

* systemd-networkd-wait-online.service is triggered twice during the boot, so the total wait time is 4 minutes.

* `systemctl is-system-running` returns `degraded` because the unit failed to start.

* Users can fix this by manually editing the netplan config and dropping the undesired network interfaces, or marking them as optional. A reboot after this works fine (no wait time, is-system-running returning `running`).

* Subiquity should mark install-time unconfigured interfaces optional, or avoid configuring them at all if they are set as "disabled" at install time. (This would be my preference: if an interface is "disabled" I don't want it to be enabled and actively sending dhcp requests, but I'm sure there are good users stories that call for enabling dhcp4 by default.)

* This can mitigated by a subiquity refresh, however fully offline installs (where at least 1 network interface is present) will still hit the bug.

* Is it too late to attempt a respin for 24.04 images.