The field pos_employee_ids (pos_hr) links hr employees records to
settings records
but this model isn't readable for Pos Administrators by default.
This commit gives read rights on hr.employee model to settings users,
reusing a confusing existing ACL whose name targeted system users,
whereas the group effectively targeted was the internal users.
Since this rule didn't give any rights, we might as well correctly
replace
it so that the name can match its purpose.
Part-of: odoo/odoo#91909