fdo#59329 Fix docked window border lines

This patch completes the missing border lines. This is intended
for versions 4.1 and 4.2 only.

Change-Id: Ib15cb3b01dca4631f643a0036475cf684793d256
Reviewed-on: https://gerrit.libreoffice.org/8413
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>