Add ssn_hash as optional column to by-name-list schema

Currently, if `ssn_hash` is in the matching keys, the matcher crashes when it tries to load the by name list. Adding this to the schema will allow users to use both hashed SSNs and by name lists.

Locate the by-name-list schema and the matcher entry point that loads it. Reproduce the crash with ssn_hash in the matching keys, then verify that the schema accepts ssn_hash as optional and the by-name-list loads successfully with hashed SSNs.

Written by the indexing model from the issue text.