Firebase response update.

Updated the Firebase SendAsync() error response so that it is ready to be used by the caller.
Also added the error details section to the http response message.

Author: Thomr77

CorePush/Firebase/FirebaseError.cs

@@ -2,7 +2,14 @@
 
 public class FirebaseError
 {
+    public class Detail
+    {
+        public string Type { get; set; }
+        public string ErrorCode { get; set; }
+    }
+
+    public int Code { get; set; }
     public string Message { get; set; }
     public string Status { get; set; }
-    public int Code { get; set; }
+    public Detail[] Details { get; set; }
 }

CorePush/Firebase/FirebaseSender.cs

@@ -108,7 +108,7 @@ public async Task<PushResult> SendAsync(object payload, CancellationToken cancel
         return new PushResult((int) response.StatusCode,
             response.IsSuccessStatusCode,
             firebaseResponse.Name ?? firebaseResponse.Error?.Message,
-            responseString);
+            firebaseResponse.Error?.Status);
     }
 
     private async Task<string> GetJwtTokenAsync()