feat: Updated the search result fly-out menu design (#8203)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/javascript/shared/mixins/messageFormatterMixin.js

@@ -21,5 +21,20 @@ export default {
 
       return `${description.slice(0, 97)}...`;
     },
+
+    highlightContent(content = '', searchTerm = '', highlightClass = '') {
+      const plainTextContent = this.getPlainText(content);
+
+      // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#escaping
+      const escapedSearchTerm = searchTerm.replace(
+        /[.*+?^${}()|[\]\\]/g,
+        '\\$&'
+      );
+
+      return plainTextContent.replace(
+        new RegExp(`(${escapedSearchTerm})`, 'ig'),
+        `<span class="${highlightClass}">$1</span>`
+      );
+    },
   },
 };