How to exclude non-essential events from logging such as tab closed or session closed?
There is no method to individually control events like 'tab closed' and 'session ended'. You can turn off categorized set of events. In this case, these events come under logging category 'Network Statistics'.
Visit Management GUI -> Profiles -> Activity log profiles -> Find logging profile active now with green tick icon and click 'update' button at right -> You will see popup and uncheck 'Network Statistics' in under 'Network Events'.