servo: Merge #8812 - M1504: Implement basic support for withCredentials API (from jitendra29:support-withCredentials); r=jdm

The pull request includes the following task:

* Implemented basic network-level support by adding a member to LoadData that is used by http_loader.rs to conditionally exclude cookies from the HTTP request if the flag is false (default true)

Source-Repo: https://github.com/servo/servo
Source-Revision: 217a55a7854ec3a843bb94f50a8952c61d5fcc2a

servo/components/script/script_task.rs

@@ -2013,6 +2013,7 @@ impl ScriptTask {
             data: load_data.data,
             cors: None,
             pipeline_id: Some(id),
+            credentials_flag: true,
         }, LoadConsumer::Listener(response_target), None)).unwrap();
 
         self.incomplete_loads.borrow_mut().push(incomplete);