LibGfx+LibWeb: Store Typeface and Font-related types in RefPtr to const

Author: https://github.com/ADKaster
Commit: be2dd91289
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4362
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/Hendiadyoin1

Libraries/LibWeb/Layout/TextNode.h

@@ -30,7 +30,7 @@ public:
 
     struct Chunk {
         Utf8View view;
-        NonnullRefPtr<Gfx::Font> font;
+        NonnullRefPtr<Gfx::Font const> font;
         size_t start { 0 };
         size_t length { 0 };
         bool has_breaking_newline { false };