Allow drag and drop to create filter for the second time too
Allow drag and drop to create filter for the second time too

Fix https://github.com/uwdata/voyager2/issues/238

uwdata/vega-lite-ui,uwdata/vega-lite-ui,vega/vega-lite-ui,uwdata/vega-lite-ui,vega/vega-lite-ui,vega/vega-lite-ui