fix segment

Author: ABTastyAdel

lib/hits/segment.dart

@@ -10,7 +10,10 @@ class Segment extends BaseHit {
   @override
   Map<String, Object> get bodyTrack {
     var customBody = new Map<String, Object>();
-    customBody.addAll({"s": persona, "t": typeOfEvent});
+// Convert persona values to String
+    Map<String, String> personaString =
+        persona.map((key, value) => MapEntry(key, value.toString()));
+    customBody.addAll({"s": personaString, "t": typeOfEvent});
     // Add commun body
     customBody.addAll(super.communBodyTrack);
     return customBody;