fdo#69358 only draw native style when toolbar is docked on top

Change-Id: I194a34881a6bd7cc14ef342d9305449094154696
Reviewed-on: https://gerrit.libreoffice.org/7920
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>