Add option to maintain selections on response action buttons

Rework the existing logic where items get de-selected automatically when you click outside the group or click a different option in the group (goal is a non-breaking, opt-in change). 

Logic currently lives here: https://github.com/patternfly/chatbot/blob/main/packages/module/src/ResponseActions/ResponseActions.tsx#L61

We should have a demo with tests, as well as new code with new prop.
