fdo#82278 SfxUInt16Item -> SfxInt16Item

A regression of 2245288574ef77b09416872326b4543c82790815.
VerbID can be negative.

Change-Id: Ib242376696346ab310031d1b7c5c74362fb4b3d1
Reviewed-on: https://gerrit.libreoffice.org/10823
Reviewed-by: Maxim Monastirsky <momonasmon@gmail.com>
Tested-by: Maxim Monastirsky <momonasmon@gmail.com>