quic-channels: CreateQuicChannel send creator's graph head

[djohnson-spideroak]

When creating a QUIC channel, we need to include the head of the graph of the device initiating the channel. This can be used by the receiver to properly process the command or fetch any commands it needs to process the command.

cc @elagergren-spideroak @jdygert-spok @benz-spideroak

Ref: aranya-project/aranya-docs#24 (comment)