Writer does not support selection, so don't claim it would

Though it doesn't change anything UI wise.
See also commit cb9d99db

Change-Id: Ic5e0e411325945f91a00b58da5341eeecd7b6623
Reviewed-on: https://gerrit.libreoffice.org/42500Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>

filter/source/config/fragments/filters/writer_png_Export.xcu

@@ -16,7 +16,7 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 -->
     <node oor:name="writer_png_Export" oor:op="replace">
-        <prop oor:name="Flags"><value>EXPORT ALIEN 3RDPARTYFILTER SUPPORTSSELECTION</value></prop>
+        <prop oor:name="Flags"><value>EXPORT ALIEN 3RDPARTYFILTER</value></prop>
         <prop oor:name="UIComponent"><value>com.sun.star.svtools.SvFilterOptionsDialog</value></prop>
         <prop oor:name="FilterService"><value>com.sun.star.comp.GraphicExportFilter</value></prop>
         <prop oor:name="UserData"><value></value></prop>