[bugfix] add support for numeric nodes in Sankey (#5154)
[bugfix] add support for numeric nodes in Sankey (#5154)

* [bugfix] add support for numeric nodes in Sankey

closes https://github.com/apache/incubator-superset/issues/5142

* lint

apache/incubator-superset,airbnb/caravel,mistercrunch/panoramix,apache/incubator-superset,mistercrunch/panoramix,zhouyao1994/incubator-superset,mistercrunch/panoramix,airbnb/superset,timifasubaa/incubator-superset,mistercrunch/panoramix,dmigo/incubator-superset,airbnb/superset,airbnb/superset,airbnb/superset,timifasubaa/incubator-superset,dmigo/incubator-superset,airbnb/caravel,zhouyao1994/incubator-superset,airbnb/caravel,dmigo/incubator-superset,apache/incubator-superset,timifasubaa/incubator-superset,apache/incubator-superset,airbnb/caravel,timifasubaa/incubator-superset,dmigo/incubator-superset,zhouyao1994/incubator-superset,zhouyao1994/incubator-superset,zhouyao1994/incubator-superset,apache/incubator-superset