In particular, in the regtests, with incoming peers, we can have multiple transports open with the same node simultaneously
(see e.g. lnworker._request_force_close_from_backup).
We now use the first few bytes of peer_pubkey, as that is potentially familiar to users,
and the first few bytes of sha256(id(self)) to mitigate collisions in case the peer_pubkeys collide.
log excerpt:
```
I/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | handshake done for 030f0bf260acdbd3edcad84d7588ec7c5df4711e87e6a23016f989b8d3a4147230@163.172.94.64:9735
D/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | Sending INIT
I/P | lnpeer.Peer.[LNWallet, 03933884aa-5e5dce45] | handshake done for 03933884aaf1d6b108397e5efe5c86bcf2d8ca8d2f700eda99db9214fc2712b134@34.250.234.192:9735
D/P | lnpeer.Peer.[LNWallet, 03933884aa-5e5dce45] | Sending INIT
D/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | Received INIT
I/P | lnpeer.Peer.[LNWallet, 02651acf4a-79696c42] | handshake done for 02651acf4a7096091bf42baad19b3643ea318d6979f6dcc16ebaec43d5b0f4baf2@82.119.233.36:19735
D/P | lnpeer.Peer.[LNWallet, 02651acf4a-79696c42] | Sending INIT
D/P | lnpeer.Peer.[LNWallet, 03933884aa-5e5dce45] | Received INIT
I/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | saved remote_update
D/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | Received CHANNEL_REESTABLISH
```
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