[SSSD] [sssd PR#5326][+Ready to push] sss_nss_idmap-tests: fixed error in iteration over `test_data`

[pbrezina]

  URL: https://github.com/SSSD/sssd/pull/5326
Title: #5326: sss_nss_idmap-tests: fixed error in iteration over `test_data`

Label: +Ready to push