Update fetch-http-client.ejs

Author: Untaek

templates/base/http-clients/fetch-http-client.ejs

@@ -121,6 +121,10 @@ export class HttpClient<SecurityDataType = unknown> {
               property.forEach(element => {
                 append(formData, key, element)
               })
+            } else if (Array.isArray(property)) {
+              property.forEach((element) => {
+                append(formData, key, element)
+              })
             } else {
               append(formData, key, property)
             }