provide the messageData in the onComplete function

[howlowck]

Is your feature request related to a problem? Please describe.
There is not a way to get the messageData easily in the onComplete function.

Describe the solution you'd like
We should have a way to pass the current messageData to the user in the onComplete function

Describe alternatives you've considered
the only way is to create the abilities function with the context in its outer scope. This might have memory implications when node is running thousands of conversations. (each one would have a separate abilities object in memory)

Additional context
See echoBot in the wolf-botbuilder repo for example.

[howlowck]

This feature is in the codebase already. The function is in the getStateFuncs object