fix some issues with ClientDisconnect

[MilonPL]

fixes an issue with ClientDisconnect (and by extension the DisconnectCommand)

turns out that DisconnectCommand is sort of a fucky-wucky

• If you use it while attempting to connect to a server, you get stuck in quantum superposition state of not connecting while connecting

• if you use it while attempting to connect in dev env, you get stuck in a void

the issue was that we weren't properly handling disconnects during active connection attempts - the code assumed you were already connected when trying to disconnect (2017 code my beloved)

now you can actually disconnect while connecting without breaking the universe 👍

[MilonPL]

@PJB3005 ready for re-review
Fixed it by handling cancellation in CCHappyEyeballs, turns out we weren't catching cancelled connection attempts during the handshake when connecting to non-responsive servers

[PJB3005]

Adding that try catch to AwaitNonInitStatusChange doesn't seem like it makes a lot of sense to me.

Reading the code, there's already a try catch for cancellation around most of the logic, but it seems like it's erroneously catching on TaskCanceledException instead of OperationCanceledException (definitely my fault). Does fixing that fix it?

[PJB3005]

Also figured I'd mention this: we can probably replace most of the logic in CCHappyEyeballs with usage of the HappyEyeballsHttp.ParallelTask<T> that I've since created. But it's really not that important so whatever.