Disable dangling ptr check for PendingRequest::request_ (fixes #3743)

The InterceptedRequestHandlerWrapper object may be deleted (likely via
~InterceptedRequest) while the task to call
InterceptedRequestHandlerWrapper:ContinueCreateURLLoaderNetworkObserver
is still pending. That binding holds a
WeakPtr<InterceptedRequestHandlerWrapper> (which is now nullptr)
resulting in the bound std::unique_ptr<PendingRequest> being deleted
while still holding a raw_ptr<network::ResourceRequest> to the
already-deleted object. This is always safe (raw_ptr will never be
dereferenced) because of the WeakPtr check.

libcef/browser/net_service/resource_request_handler_wrapper.cc

@@ -147,7 +147,7 @@ class InterceptedRequestHandlerWrapper : public InterceptedRequestHandler {
     }
 
     const int32_t id_;
-    raw_ptr<network::ResourceRequest> request_;
+    raw_ptr<network::ResourceRequest, DisableDanglingPtrDetection> request_;
     const bool request_was_redirected_;
     OnBeforeRequestResultCallback callback_;
     CancelRequestCallback cancel_callback_;