radosgw-admin: 'user create' rejects uids matching the account id format

`parse_owner()` relies on `rgw::account::validate_id()` to disambiguate
between user ids and account ids. reject attempts to create a user with
an ambiguous user id

Fixes: https://tracker.ceph.com/issues/69043

Signed-off-by: Casey Bodley <[email protected]>

Author: cbodley

src/rgw/driver/rados/rgw_user.cc

@@ -1755,7 +1755,11 @@ int RGWUser::execute_add(const DoutPrefixProvider *dpp, RGWUserAdminOpState& op_
   user_info.display_name = display_name;
   user_info.type = TYPE_RGW;
 
-  // tenant must not look like a valid account id
+  // user/tenant must not look like a valid account id
+  if (rgw::account::validate_id(uid.id)) {
+    set_err_msg(err_msg, "uid must not be formatted as an account id");
+    return -EINVAL;
+  }
   if (rgw::account::validate_id(uid.tenant)) {
     set_err_msg(err_msg, "tenant must not be formatted as an account id");
     return -EINVAL;