The problem, as seen by the user is that during shape text edit,
sometimes just traveling with the cursor causes invalidations, which is
unexpected.

What happens is sd::Window::KeyInput() invokes
sd::DrawViewShell::MakeVisible(), which does a pixel-to-logic
conversion, but because the map mode is in general disabled in the LOK
case, nothing happens. Then a bit later aVisArea.IsInside(rRect) fails,
as it compares pixel and logic units, which results in
sd::ViewOverlayManager::UpdateTags() scheduling an async call to
sd::ViewOverlayManager::UpdateTagsHdl(), which at the end causes a full
invalidation in sd::SmartTagSet::remove().

Fix the situation by temporarily enabling map mode, so we don't detect
a visible cursor area as a non-visible one.

Change-Id: I6d16f24d13143dc263a89317fbc38111e652c0ac