refactor: user auth check for ajax methods

ajax/confirmPaymentIntent.php

@@ -31,5 +31,6 @@ function ($orderHash) {
             ]);
         }
     },
-    ['orderHash']
+    ['orderHash'],
+    'Permission::checkUser'
 );

ajax/confirmSubscription.php

@@ -31,5 +31,6 @@ function ($orderHash) {
             ]);
         }
     },
-    ['orderHash']
+    ['orderHash'],
+    'Permission::checkUser'
 );

ajax/createPaymentIntent.php

@@ -32,5 +32,6 @@ function ($orderHash, $paymentMethodId) {
             ]);
         }
     },
-    ['orderHash', 'paymentMethodId']
+    ['orderHash', 'paymentMethodId'],
+    'Permission::checkUser'
 );