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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- [X] `./mach build -d` does not report any errors
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- [X] These changes fix #36108 

<!-- Either: -->
- [X] There are tests for these changes

---------

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

components/script/dom/htmliframeelement.rs

@@ -271,6 +271,7 @@ impl HTMLIFrameElement {
                 document.get_referrer_policy(),
                 Some(window.as_global_scope().is_secure_context()),
                 Some(document.insecure_requests_policy()),
+                document.has_trustworthy_ancestor_or_current_origin(),
             );
             let element = self.upcast::<Element>();
             load_data.srcdoc = String::from(element.get_string_attribute(&local_name!("srcdoc")));
@@ -362,6 +363,7 @@ impl HTMLIFrameElement {
             referrer_policy,
             Some(window.as_global_scope().is_secure_context()),
             Some(document.insecure_requests_policy()),
+            document.has_trustworthy_ancestor_or_current_origin(),
         );
 
         let pipeline_id = self.pipeline_id();
@@ -407,6 +409,7 @@ impl HTMLIFrameElement {
             document.get_referrer_policy(),
             Some(window.as_global_scope().is_secure_context()),
             Some(document.insecure_requests_policy()),
+            document.has_trustworthy_ancestor_or_current_origin(),
         );
         let browsing_context_id = BrowsingContextId::new();
         let webview_id = window.window_proxy().webview_id();