Add a system act.
Usage:
resultBuilder.endSession().System act.
End the user session.
Framework behavior:
ask-core.ResponseBuilder.withShouldEndSession(true).Skill/device behavior:
Place the user session in the idle state.
ask-core.ResponseBuilder.withShouldEndSession(undefined).Skill/device behavior:
Determines if the result has an initiative act.
Builder that creates a ControlResult.