fdo#67040 There’s a valid use case to enable manual resizing in this dialog

Change-Id: I8af9ad0dd0bf09bd84aea7d6c9c5d5800ab8792c
Reviewed-on: https://gerrit.libreoffice.org/12448
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>