Error expected on DataConnection when not establishing a connection

When a DataConnection fails to establish, for example, due to connecting to an invalid ID or to one's own ID, I would expect the `dataConnection.on('error', () => {...})` callback to be executed. Instead, only `peer.on('error', () => {})` catches such kinds of errors. This is especially annoying when you want to for example connect to multiple peers at once since we cannot know which one has failed to connect, making it hard to tell the user which peer(s) has issues.