This handles a case where KDE shows a notification saying
'PIM Maintenance (Finished)', like this:
https://openqa.fedoraproject.org/tests/477345#step/desktop_notifications/34
we need to click it away for the desktop_notification test to
pass. It also clarifies the difference between this notification
and the eternal 'akonadi_migration_agent is doing something'
popup in the needle names and comments. It also replaces the
'check_screen then assert_and_click if found' pattern in several
notifications-related places with the better 'check_screen then
click_lastmatch if found' pattern now available upstream.
Signed-off-by: Adam Williamson <awilliam@redhat.com>
