...lost with 2ea92be9 "convert SC_CONVERT
constants to scoped enum".  And indeed, e.g., opening the document from
<https://bugs.documentfoundation.org/show_bug.cgi?id=114932#c2> through steps 1
and 2 in a UBSan build reports a use of an uninitialized (bad-valued) bool in
ScNavigatorSettings::IsExpanded.

Change-Id: If0dfadc6bd8033e61e334f59b3028ab005a892cd
Reviewed-on: https://gerrit.libreoffice.org/47767Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>