chore: remove duplicate part

Author: horike37

lib/apiGateway/schema.js

@@ -225,28 +225,6 @@ const rangeKey = Joi.when('action', {
   })
 })
 
-const stringOrGetAtt = (propertyName, attributeName) => {
-  return Joi.alternatives().try([
-    Joi.string(),
-    Joi.object({
-      'Fn::GetAtt': Joi.array()
-        .length(2)
-        .ordered(
-          Joi.string().required(),
-          Joi.string()
-            .valid(attributeName)
-            .required()
-        )
-        .required()
-    }).error(
-      customErrorBuilder(
-        'object.child',
-        `"${propertyName}" must be in the format "{ 'Fn::GetAtt': ['<ResourceId>', '${attributeName}'] }"`
-      )
-    )
-  ])
-}
-
 const request = Joi.object({
   template: Joi.object().required()
 })