Change KeyedPercentiles value type from long to double (#5108)

(cherry picked from commit 2fbfdad)

Author: flobernd

specification/_types/aggregations/Aggregate.ts

@@ -157,7 +157,7 @@ type Percentiles = KeyedPercentiles | Array<ArrayPercentilesItem>
 // <key_name>_as_string? string - present if a format was provided
 //
 // Note: defined as type alias and not inline, as some clients may want to implement it in a more usable way.
-type KeyedPercentiles = Dictionary<string, string | long | null>
+type KeyedPercentiles = Dictionary<string, string | double | null>
 
 export class ArrayPercentilesItem {
   key: string