Investiaget the need for a connection state field in cluster connetion

[shachlanAmazon]

https://github.com/amazon-contributing/redis-rs/blob/2518c0ffd4141fc0852cd05ffa0d549f073885a1/redis/src/cluster_async/mod.rs#L213C12-L213C27

This field might've become unnecessary after adding the lock over the connection state.