TF-2160 Use loading attribute replace IntersectionObserver

(cherry picked from commit 88362cab421f0962dc0103bd165d70850668043e)

core/lib/presentation/utils/html_transformer/html_utils.dart

@@ -61,40 +61,6 @@ class HtmlUtils {
     }
   ''';
 
-  static const scriptLazyLoadImage = '''
-    <script type="text/javascript">
-      const lazyImages = document.querySelectorAll("img.lazy-loading");
-      
-      const options = {
-        root: null, // Use the viewport as the root
-        rootMargin: "0px",
-        threshold: 0 // Specify the threshold for intersection
-      };
-      
-      const handleIntersection = (entries, observer) => {
-        entries.forEach((entry) => {
-          if (entry.isIntersecting) {
-            const img = entry.target;
-            const src = img.getAttribute("data-src");
-      
-            // Replace the placeholder with the actual image source
-            img.src = src;
-            img.removeAttribute("data-src");
-      
-            // Stop observing the image
-            observer.unobserve(img);
-          }
-        });
-      };
-      
-      const observer = new IntersectionObserver(handleIntersection, options);
-      
-      lazyImages.forEach((image) => {
-        observer.observe(image);
-      });
-    </script>
-  ''';
-
   static String customCssStyleHtmlEditor({TextDirection direction = TextDirection.ltr}) {
     if (PlatformInfo.isWeb) {
       return '''