Remove duplicated trashed document previews

Side effect of source column inheritance added in
06c3ef6583.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/documents/apps.py

@@ -310,14 +310,6 @@ class DocumentsApp(MayanAppConfig):
             attribute='label', is_identifier=True, is_sortable=True,
             source=DeletedDocument
         )
-        SourceColumn(
-            func=lambda context: document_page_thumbnail_widget.render(
-                instance=context['object']
-            ), label=_('Thumbnail'), source=DeletedDocument
-        )
-        SourceColumn(
-            attribute='document_type', is_sortable=True, source=DeletedDocument
-        )
         SourceColumn(
             attribute='deleted_date_time', source=DeletedDocument
         )