Update the Search dialog when items in the calendar change

When `CalendarView::slotModifyFinished` fires, the calendar has not been
updated, so the `calendar()->events` call in `SearchDialog::updateView`
returns stale events.  This patch connects `SearchDialog::updateView` to
the `calendarChanged` signal, which is what is done for the Event List.
1 job for release/21.08 in 2 minutes and 13 seconds (queued for 2 seconds)
Name Stage Failure
failed
build_clazy_clang_tidy Build
No job log