Cleanup Rubocop Exceptions

As part of the test cleanup we added rubocop and created exceptions in https://github.com/apsislabs/phi_attrs/blob/master/.rubocop.yml to not impact existing behavior.

In the PR for this each of the `# TODO: RUBOCOP` should be an individual commit that removes the exception and fixes the offending file so that we can do a step by step comparison.

Start with .rubocop.yml and search the repository for each `# TODO: RUBOCOP` marker. For each exception, inspect the referenced offending file and make a separate commit that removes the exception and preserves existing behavior; compare each step with the prior state.

Written by the indexing model from the issue text.