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.