magento#12209: Substitution payment method - Incorrect message

- fixed message showing if payment method is not available

Author: AndrewMun

app/code/Magento/Payment/view/adminhtml/templates/info/substitution.phtml

@@ -10,6 +10,8 @@
  */
 ?>
 <div>
-    <?php $block->escapeHtml($block->getMethod()->getTitle());?>
+    <?= $block->getMethod()->getTitle()
+        ? $block->escapeHtml($block->getMethod()->getTitle())
+        : $block->escapeHtml(__('Payment method')); ?>
     <?= $block->escapeHtml(__(' is not available. You still can process offline actions.')) ?>
 </div>