Thousands of ZIP codes are in the ZIP code list but are missing from the output

[tomwillis608]

Describe the bug
There are ZIP codes in various states that are not found in the SSA CC to ZIP Code final output

To Reproduce
Steps to reproduce the behavior:

1. PYTHONPATH=. python3 ssacc/cli.py -r 0
   There are 42522 ZIP codes in the ZIP code list but only 38408 in the output.

Expected behavior
All ZIP codes have a SSA county

Additional context
Discovered when adding unit tests to validate_files and discovered that validate_all_zips() was not acting as expected and was not flagging missing ZIP codes correctly.