validation doc gate doing nothing and just skipping all sites validation

Describe the bug Current airship-treasuremap-validate-site-docs gate is doing nothing and just skipping all sites validation.

Steps To Reproduce https://zuul.opendev.org/t/openstack/build/6e0e1b2873f742c7911cb99ade1efdd1/console

for site in $(ls ${MANIFEST_ROOT}/${site_root})
sites_to_skip=(az-test-site docker-test-site openstack-test-site)
[[ az-test-site docker-test-site openstack-test-site =~ reference-airship-core ]]
'[' '!' -z test-site ']'
'[' reference-airship-core '!=' test-site ']'
continue
for site in $(ls ${MANIFEST_ROOT}/${site_root})
sites_to_skip=(az-test-site docker-test-site openstack-test-site)
[[ az-test-site docker-test-site openstack-test-site =~ reference-multi-tenant ]]
'[' '!' -z test-site ']'
'[' reference-multi-tenant '!=' test-site ']'
continue
for site in $(ls ${MANIFEST_ROOT}/${site_root})
sites_to_skip=(az-test-site docker-test-site openstack-test-site)
[[ az-test-site docker-test-site openstack-test-site =~ virtual-airship-core ]]
'[' '!' -z test-site ']'
'[' virtual-airship-core '!=' test-site ']'
continue
for site in $(ls ${MANIFEST_ROOT}/${site_root})
sites_to_skip=(az-test-site docker-test-site openstack-test-site)
[[ az-test-site docker-test-site openstack-test-site =~ virtual-multi-tenant ]]
'[' '!' -z test-site ']'
'[' virtual-multi-tenant '!=' test-site ']'
continue

Expected behavior Validation of docs need to be performed on all sites present in treasuremap repo.

Environment

airshipit / treasuremap