TF-1487 Fix run command flutter test

(cherry picked from commit 798b5613d2cc98223c7c236545c244c1499dc982)

forward/test/forward/get_forward_method_test.dart

@@ -64,8 +64,7 @@ void main() {
           },
           headers: {
             "accept": "application/json;jmapVersion=rfc-8621",
-            "content-type": "application/json; charset=utf-8",
-            "content-length": 212
+            "content-length": 292
           });
 
       final httpClient = HttpClient(dio);

forward/test/forward/set_forward_method_test.dart

@@ -98,8 +98,7 @@ void main() {
         },
         headers: {
           "accept": "application/json;jmapVersion=rfc-8621",
-          "content-type": "application/json; charset=utf-8",
-          "content-length": 420
+          "content-length": 765
         }
       );