fix design request

lib/features/showrooms/presentation/pages/design_request_detail_page.dart

@@ -305,12 +305,14 @@ class DesignRequestDetailPage extends ConsumerWidget {
                         value: request.subject,
                       ),
 
-                      if (request.plainDescription.isNotEmpty) ...[
+                      if (request.description != null &&
+                          request.description!.isNotEmpty) ...[
                         const SizedBox(height: 12),
                         DescriptionItem(
                           label: 'Mô tả chi tiết:',
-                          value: request.plainDescription,
+                          value: request.description!,
                           isMultiLine: true,
+                          isHtml: true,
                         ),
                       ],
                     ],