update email template

app/Exceptions/InvalidTemplateVariableException.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace App\Exceptions;
+
+use RuntimeException;
+
+class InvalidTemplateVariableException extends RuntimeException
+{
+    public function __construct(string $scenario, array $invalidKeys)
+    {
+        parent::__construct(sprintf(
+            'Template "%s" chứa variable không hợp lệ (chưa khai báo trong metadata.variables): %s',
+            $scenario,
+            implode(', ', $invalidKeys),
+        ));
+    }
+}