(#17474) Make it possible to return `false` from a terminus

This manifested as an inability to retrieve the value `false` from hiera using
data bindings. The find method on Puppet::Indirection interpreted this as no
value being returned.
Merge branch 'ticket/17474-indirection-false' of https://github.com/pcarlisle/puppet

* 'ticket/17474-indirection-false' of https://github.com/pcarlisle/puppet:
  (#17474) Make it possible to return `false` from a terminus