Coinbase `level2` channel authentication required

[brucify]

https://docs.cloud.coinbase.com/exchange/docs/changelog#2023-aug-01

2023-AUG-01

The following WebSocket feeds now enforce authentication (in addition to the User channel):

[Full channel](https://docs.cloud.coinbase.com/exchange/docs/websocket-channels#full-channel)
[Level2 channel](https://docs.cloud.coinbase.com/exchange/docs/websocket-channels#level2-channel)
[Level3 channel](https://docs.cloud.coinbase.com/exchange/docs/websocket-channels#level3-channel)

See WebSocket Authentication for instructions.

https://docs.cloud.coinbase.com/exchange/docs/websocket-auth