ProtobufConverter.from_recap fails with "Struct must have an alias"

[criccomini]

This error is technically correct, but really annoying since to_recap often doesn't set an alias for a struct. I'd like PB's from_recap to work with Structs that have no aliases (maybe it picks up name or uses some default if alias is unset?).

[criccomini]

Make sure to enable the test_cli.py and test_gateway.py integration tests for protobuf schemas once this is done.