fix: GossipSub peer propagation to include FloodSub peers

[paschal533]

What was wrong?

When a node publishes a message immediately after connecting to a peer, py-libp2p sometimes crashes with:

KeyError: <PeerID>

This happens in pubsub/gossipsub.py, where self.peer_protocol[peer_id] is accessed before the identify handshake has finished. The handshake is asynchronous, so peer_protocol may not yet contain the connected peer.

Issue #887

How was it fixed?

• Guarded against missing entries in peer_protocol
• Optionally, queue publishes until identify completes.

Summary of approach.

To-Do

• Clean up commit history
• Add or update documentation related to these changes
• Add entry to the release notes

Cute Animal Picture

[seetadev]

@paschal533 : Great, thank you for submitting the PR.

Would recommend @Winter-Soren, @lla-dane and @sumanjeet0012 to share feedback on the PR. Appreciate your efforts.

[sumanjeet0012]

@seetadev This PR introduces only an additional check before accessing it. We can proceed with merging this PR.