Token JSBin example needs the subscribe button to be changed

[tomczoink]

Currently the subscribe option in https://jsbin.ably.io/oqasav/1/edit for a token will only check if the library is able to listen on the client-side, not if it has actually successfully subscribed to a channel and is able to listen to updates. We need to make it test this by instead publishing a message, and seeing if the subscriber receives it. Same goes for presence subscribing.

┆Issue is synchronized with this Jira Bug by Unito