fix: only attempt to subscribe/unsubscribe to channels when socket id is set

[nicobritos]

• Only attempt to subscribe to a private channel if socket id is set, as it is necessary for authenticating a private channel on the server side.

[kerimamansaryyev]

Well done, @nicobritos. Thank you very much!

[kerimamansaryyev]

I think, the same should be done on Public Channels

[kerimamansaryyev]

Checking if [connectionDelegate.socketId] is set on both subscription and unsubscription of both type of Channels

[kerimamansaryyev]

@nicobritos , Please have a look at the latest changes to the branch. If it's ok, I will merge it to master.

[nicobritos]

@Mcfugger yeah, I think it's OK. I didn't notice but unsubscribing a channel when the socket id is null (therefore, the connection has been closed) makes no sense, so I think it ok.

[kerimamansaryyev]

@Mcfugger yeah, I think it's OK. I didn't notice but unsubscribing a channel when the socket id is null (therefore, the connection has been closed) makes no sense, so I think it ok.

Actually, it does make sense - it may be waste calls to the server even it ignores them