The client needs to know the set of transit IPs that are assigned
to each connector, so when we register transit IPs with the connector
we also need to assign them to that connector in the addrAssignments.
We identify the connector by node public key to match the peer information
that is available when the ExtraWireguardAllowedIPs hook will be invoked.
Fixestailscale/corp#38127
Signed-off-by: George Jones <george@tailscale.com>