TF-1912 Sanitize html for email content when type is text/plain

(cherry picked from commit 169ede2f8b59cdf0362ad449d1182597cd4e5dee)

core/lib/presentation/utils/html_transformer/text/sanitize_html_transformers.dart

@@ -0,0 +1,17 @@
+
+import 'dart:convert';
+
+import 'package:core/presentation/utils/html_transformer/base/text_transformer.dart';
+import 'package:core/utils/app_logger.dart';
+
+class SanitizeHtmlTransformers extends TextTransformer {
+
+  const SanitizeHtmlTransformers();
+
+  @override
+  String process(String text) {
+    final htmlEncoded = const HtmlEscape().convert(text);
+    log('HtmlSanitizerTransformers::process:htmlEncoded: $htmlEncoded');
+    return htmlEncoded;
+  }
+}