script: Fix check for document root when targeting CSP events (#37474)

The check was incorrect, where it was never matching and always
discarding the element. Instead, we should check the owner document,
which is the shadow-including root of the node.

Part of #4577

---------

Signed-off-by: Tim van der Lippe <tvanderlippe@gmail.com>

components/script/dom/htmliframeelement.rs

@@ -168,7 +168,7 @@ impl HTMLIFrameElement {
             if let Some(window_proxy) = window_proxy {
                 if document
                     .global()
-                    .should_navigation_request_be_blocked(&load_data)
+                    .should_navigation_request_be_blocked(&load_data, Some(self.upcast()))
                 {
                     return;
                 }