f38 live workstation and network manager wait online

[Tom Horsley]

Just noticed this while testing my multi-boot USB stick with scads
of ISO images:

In Fedora 39, the boot spends an annoying amount of time imagining
that it can wait for a network to be up, but the physical ethernet
port is connected (via crossover cable) to a device which will definitely
not be providing any DHCP. I suspect if I unplugged the cable, it would
boot faster since nothing would look like a live signal.

I tried booting the Fedora 38 workstation live ISO, and it didn't
spend a lot of time waiting for the network, so something is different
from f38 to f39 (maybe the "no limit" timeout?).

They both eventually booted up, so it obviously isn't a major issue.