LibWeb: Only invalidate styles if a @media rule changes match status

Author: https://github.com/AtkinsSJ
Commit: fd24782d85
Pull-request: https://github.com/SerenityOS/serenity/pull/12601

Userland/Libraries/LibWeb/CSS/CSSRuleList.h

@@ -52,7 +52,8 @@ public:
     DOM::ExceptionOr<unsigned> insert_a_css_rule(NonnullRefPtr<CSSRule>, u32 index);
 
     void for_each_effective_style_rule(Function<void(CSSStyleRule const&)> const& callback) const;
-    void evaluate_media_queries(DOM::Window const&);
+    // Returns whether the match state of any media queries changed after evaluation.
+    bool evaluate_media_queries(DOM::Window const&);
 
 private:
     explicit CSSRuleList(NonnullRefPtrVector<CSSRule>&&);