LibWeb: Avoid possible infinite recursion in Document::is_fully_active

Author: https://github.com/shannonbooth
Commit: https://github.com/LadybirdBrowser/ladybird/commit/bfc28bd6215
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2081

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -2679,7 +2679,7 @@ bool Document::is_fully_active() const
         return true;
 
     auto container_document = navigable->container_document();
-    if (container_document && container_document->is_fully_active())
+    if (container_document && container_document != this && container_document->is_fully_active())
         return true;
 
     return false;