add words in admin.json

resource/locales/en_US/admin/admin.json

@@ -275,6 +275,7 @@
     "external_accounts":"External accounts",
     "create_external_account":"Create external account",
     "external_account_list": "External Account List",
+    "external_account_none":"No External Account",
     "invite": "Invite",
     "invited": "User was invited",
     "back_to_user_management": "Back to User Management",

resource/locales/ja_JP/admin/admin.json

@@ -273,6 +273,7 @@
     "external_accounts": "外部アカウント",
     "create_external_account":"外部アカウントの作成",
     "external_account_list": "外部アカウント一覧",
+    "external_account_none":"外部アカウントはありません",
     "invite": "招待する",
     "invited": "ユーザーを招待しました",
     "back_to_user_management": "ユーザー管理に戻る",

resource/locales/zh_CN/admin/admin.json

@@ -282,7 +282,8 @@
 		"external_account": "外部账户管理",
 		"external_accounts": "外部账户",
 		"create_external_account": "创建外部账户",
-		"external_account_list": "外部账户列表",
+    "external_account_list": "外部账户列表",
+    "external_account_none":"No External Account",
 		"invite": "邀请",
 		"invited": "已邀请用户",
 		"back_to_user_management": "返回用户管理",

src/client/js/components/Admin/ManageExternalAccount.jsx

@@ -66,7 +66,7 @@ class ManageExternalAccount extends React.Component {
          )
          : (
            <>
-           外部アカウントはありません
+             {t('admin:user_management.external_account_none')}
            </>
 )}