LibWeb+Browser: Disable Same-Origin Policy by default for now

Until we have CORS preflight checks working, this is only getting in the
way of testing and I have to disable it manually all the time.

Userland/Applications/Browser/BrowserWindow.cpp

@@ -381,7 +381,7 @@ void BrowserWindow::build_menus()
             active_tab().m_web_content_view->debug_request("same-origin-policy", action.is_checked() ? "on" : "off");
         },
         this);
-    same_origin_policy_action->set_checked(true);
+    same_origin_policy_action->set_checked(false);
     debug_menu.add_action(same_origin_policy_action);
 
     auto& help_menu = add_menu("&Help");

Userland/Libraries/LibWeb/Page/Page.h

@@ -66,7 +66,8 @@ private:
     RefPtr<BrowsingContext> m_top_level_browsing_context;
     WeakPtr<BrowsingContext> m_focused_context;
 
-    bool m_same_origin_policy_enabled { true };
+    // FIXME: Enable this by default once CORS preflight checks are supported.
+    bool m_same_origin_policy_enabled { false };
 };
 
 class PageClient {