default-unmanaged devices are unmanaged until the user explicitly activates them.  Unfortunately that was broken because no connections were in AvailableConnections for these devices.

Next, shared connections were excluded from master device ignore carrier checks, which is wrong because they are effectively static/manual connections for the master device.  Furthermore, because bridge/bond don't get a carrier until at least one of their slaves have a carrier, this meant that shared IP configuration was not applied to a bridge/bond with tun/tap/veth slaves (a common VM/container configuration such as the libvirt default) until a container/VM was started and attached to the tun/tap/veth (which only turn on the carrier when something is attached), which could be too late.  Allow shared configurations to be started immediately on master devices, ignoring carrier state.