Combines NotificationEntryManager listener interfaces (part 5).

This change combines the onEntryRemoved() and
onPerformRemoveNotification() methods on NotificationEntryListener to a
single method.  The latter method was called after the former method in
all cases where the removal of the notification was precipitated by user
action (swipe, bubble swipe, launching content intent), so it's replaced
by a boolean parameter to the former method indicating whether a user
action caused the removal.

Test: atest SystemUITests, manual
Change-Id: I448fdd68984e3c2489259940c4d3432ac5bfe320