[databases][api] Fix needed_dataformats field content

The needed dataformats were returned as referenced_dataformats
replacing the content of the field.

beat/web/databases/api.py

@@ -274,7 +274,7 @@ class RetrieveDatabaseView(views.APIView):
                     if has_access:
                         needed_dataformats.append(dataformat)
                 serializer = ReferencedDataFormatSerializer(needed_dataformats)
-                result['referenced_dataformats'] = serializer.data
+                result['needed_dataformats'] = serializer.data
 
             # Return the result
             return Response(result)