warn_error_options with empty warn or error fields does not use silence

[gshank]

Current Behavior

If you use the example in the docs for silencing warnings:

  warn_error_options:
    error: # Previously called "include"
    warn: # Previously called "exclude"
    silence: # To silence or ignore warnings
      - TestsConfigDeprecation
      - NoNodesForSelectionCriteria

it doesn't work to silence TestsConfigDeprecation. You have to remove the empty error: and warn: fields.

Expected Behavior

The example should work for silencing warnings.

Steps to Reproduce

Copy the config into dbt_project.yml in a project with a "tests:" config.

Relevant log output

18:43:15  [WARNING]: Deprecated functionality
The `tests` config has been renamed to `data_tests`. Please see
https://docs.getdbt.com/docs/build/data-tests#new-data_tests-syntax for more
information.

Additional Context