tdf#33603: sd: notes pane: force proper flush on page change

After clearing the notes pane outliner and filling with then
new content, if the new content didn't overfill the
previous' area there was a residue from the last content
visible.

Make sure it is flushed by triggering onResize() on page
change.

Which also fixes the notespane sometimes keeping the
scrollbar & scrollarea from the previous content.

Change-Id: Ibbcb0f4f316bd283e5e65bb2ebd9cf17a3b38c0e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/167489
Tested-by: Jenkins
Reviewed-by: Sarper Akdemir <sarper.akdemir@allotropia.de>

sd/source/ui/view/NotesPanelView.cxx

@@ -284,6 +284,7 @@ IMPL_LINK(NotesPanelView, EventMultiplexerListener, tools::EventMultiplexerEvent
         case EventMultiplexerEventId::MainViewRemoved:
         case EventMultiplexerEventId::MainViewAdded:
             FillOutliner();
+            onResize();
             break;
         default:
             break;