message: [slice] Fix, remove duplicate label_columns property
diff: @@ -485,9 +485,6 @@ class SliceModelView(SupersetModelView, DeleteMixin): # noqa
  edit_title = _('Edit Chart')
  can_add = False
  - label_columns = {
  - 'datasource_link': _('Datasource'),
  - }
  search_columns = (
  'slice_name', 'description', 'viz_type', 'datasource_name', 'owners',
  )
  