Check all ancestor navigable trustworthiness for mixed content (#36157)

Propagate through documents a flag that represents if any of the
ancestor navigables has a potentially trustworthy origin.

The "potentially trustworthy origin" concept appears to have gotten
confused in a couple of places and we were instead testing if a URL had
"potentially trustworthy" properties.

The main test for the ancestor navigables is
[mixed-content/nested-iframes](https://github.com/web-platform-tests/wpt/blob/master/mixed-content/nested-iframes.window.js)

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Signed-off-by: Sebastian C <sebsebmc@gmail.com>

components/script/dom/workerglobalscope.rs

@@ -296,6 +296,9 @@ impl WorkerGlobalScopeMethods<crate::DomTypeHolder> for WorkerGlobalScope {
             .use_url_credentials(true)
             .origin(global_scope.origin().immutable().clone())
             .insecure_requests_policy(self.insecure_requests_policy())
+            .has_trustworthy_ancestor_origin(
+                global_scope.has_trustworthy_ancestor_or_current_origin(),
+            )
             .pipeline_id(Some(self.upcast::<GlobalScope>().pipeline_id()));
 
             let (url, source) = match fetch::load_whole_resource(