fdo#74535: Don't forget clear the edit engine before re-using it.

Else you'd get a very comical result.

Change-Id: Ie73145dee47a8583f2e9cdb7ddb4f2d66f361dc1
(cherry picked from commit 10da10ee6ba37f4861045d1f8db0022293433cec)
Reviewed-on: https://gerrit.libreoffice.org/7936
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>