allow info.test_default in arguments

[rcannood]

Describe your changes

This PR changes the unit test to look at the .info.test_default field inside an argument. This allows a component to have an argument like this:

arguments:
  - type: integer
    name: --epochs
    default: 100
    info:
      test_default: 3

Checklist before requesting a review

• I have performed a self-review of my code

• Check the correct box. Does this PR contain:

  • Breaking changes
  • New functionality (new method, new metric, ...)
  • Major changes
  • Minor changes
  • Bug fixes

• Proposed changes are described in the CHANGELOG.md

• CI Tests succeed and look good!