Fix handling a network request body that is not a string

Fix handling a network request body that is not a string

Author: ahmed1hisham

__tests__/xhrNetworkInterceptor.spec.js

@@ -60,10 +60,10 @@ describe('Network Interceptor', () => {
 
     it('should set requestBody in network object', (done) => {
 
-        const requestBody = { data: [{ item: 'first' }, { item: 'second' }] };
+        let requestBody = { data: [{ item: 'first' }, { item: 'second' }] };
         Interceptor.enableInterception();
         Interceptor.setOnDoneCallback((network) => {
-            expect(network.requestBody).toEqual(requestBody);
+            expect(network.requestBody).toEqual(JSON.stringify(requestBody));
             done();
         })
         FakeRequest.open(method, url);

utils/XhrNetworkInterceptor.js

@@ -56,6 +56,10 @@ const XHRInterceptor = {
       var cloneNetwork = JSON.parse(JSON.stringify(network));
       cloneNetwork.requestBody = data ? data : '';
 
+      if (typeof cloneNetwork.requestBody !== "string") {
+        cloneNetwork.requestBody = JSON.stringify(cloneNetwork.requestBody);
+      }
+      
       if (this.addEventListener) {
         this.addEventListener(
           'readystatechange',