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

Though it doesn't change anything UI wise.
See also commit cb9d99dbb5a7249ca7437bd5c30c6c9374089a16

Change-Id: Ic5e0e411325945f91a00b58da5341eeecd7b6623
Reviewed-on: https://gerrit.libreoffice.org/42500
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>
diff --git a/filter/source/config/fragments/filters/writer_png_Export.xcu b/filter/source/config/fragments/filters/writer_png_Export.xcu
index a6c8d37..8dd58b3 100644
--- a/filter/source/config/fragments/filters/writer_png_Export.xcu
+++ b/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>