Add missing zh-CN translation for INVITATION-ERR-2 error code

Author: luojun96

common/i18n/zh-CN/err_invitation.json

@@ -0,0 +1,11 @@
+{
+    "error.INVITATION-ERR-0": {
+        "other": "未绑定手机号，不能创建邀请码"
+    },
+    "error.INVITATION-ERR-1": {
+        "other": "邀请码不存在"
+    },
+    "error.INVITATION-ERR-2": {
+        "other": "邀请码已存在"
+    }
+}