Base_Engine: Add ability to query suppression state of events

Now we can suppress event recording, it would be helpful to be able to query the suppression state.

This will be helpful in resolving https://github.com/BHoM/BHoM_UI/issues/485 - knowing if the events were already suppressed by the user in a UI prior to running the method will help ensure the UX for the user does not change suppression state.