Add a zombienet smoke test

[rzadp]

• Introduce a zombienet-based smoke test for the parachain.
• Remove the separate run-node job.
  • Building in release mode is tested in the new zombienet job, and making sure the binary is properly executable on both Ubuntu and macOS can be done in the other job that builds the binary in debug mode.
• The zombienet test is run on Ubuntu only at the moment. macOS can be added once we have this - it is currently number two on the developer wishlist. Alternative would be to build polkadot-sdk from scratch but I don't think we want this in this template.
• Along the way, found a bug in zombienet, proposed a fix.

[github-actions]

Hello, this is an automatic reminder that any code changes should be made to the source.