Send WillNavigate earlier during navigation startup (#37778)

The will-navigate message tells the devtools client to expect a
navigation for a browsing context. This makes the network monitor clear
any previous entries and show the requests for the new page that is
loaded. In order to support this correctly, we need to send the
navigation notification from the constellation instead of the script
thread, otherwise we silently ignore navigations triggered by the
browser URL bar.




Testing: Ran servo in devtools mode , now the requests appear for new
loaded page
Fixes: https://github.com/servo/servo/issues/37334

---------

Signed-off-by: Uthman Yahaya Baba <uthmanyahayababa@gmail.com>

components/shared/devtools/lib.rs

@@ -444,6 +444,7 @@ pub struct HttpRequest {
     pub connect_time: Duration,
     pub send_time: Duration,
     pub is_xhr: bool,
+    pub browsing_context_id: BrowsingContextId,
 }
 
 #[derive(Debug, PartialEq)]
@@ -452,6 +453,7 @@ pub struct HttpResponse {
     pub status: HttpStatus,
     pub body: Option<Vec<u8>>,
     pub pipeline_id: PipelineId,
+    pub browsing_context_id: BrowsingContextId,
 }
 
 #[derive(Debug)]