removing category cast to string in aggregation

lib/cartodb/models/dataview/aggregation.js

@@ -74,7 +74,7 @@ const specialNumericValuesColumns = () => `, nans_count, infinities_count`;
 
 const rankedAggregationQueryTpl = ctx => `
     SELECT
-        CAST(category AS text),
+        category,
         value,
         false as agg,
         nulls_count,
@@ -109,7 +109,7 @@ const rankedAggregationQueryTpl = ctx => `
 
 const aggregationQueryTpl = ctx => `
     SELECT
-        CAST(${ctx.column} AS text) AS category,
+        ${ctx.column} AS category,
         ${ctx.aggregationFn} AS value,
         false as agg,
         nulls_count,