TW-2145: Update condition for mapping formatted_body

Author: nqhhdev

lib/src/room.dart

@@ -676,7 +676,7 @@ class Room {
           getMention: getMention);
       // if the decoded html is the same as the body, there is no need in sending a formatted message
       if (HtmlUnescape().convert(html.replaceAll(RegExp(r'<br />\n?'), '\n')) !=
-          event['body']) {
+          event['body'].toString().convertLinebreaksToBr()) {
         event['format'] = 'org.matrix.custom.html';
         event['formatted_body'] = html;
       }

lib/src/utils/markdown.dart

@@ -263,7 +263,7 @@ String markdown(
   return ret;
 }
 
-extension on String {
+extension StringExtension on String {
   String convertLinebreaksToBr() {
     final parts = split('pre>');
     var convertLinebreaks = true;