Populate eligibility check description field

[prestoncabe]

User Story

As a Benefits Analyst editing a benefit
When I look to add a library check
Then I should see a brief description of the check

Acceptance Criteria

• Description column in the list of "Public Checks" is populated with the Description from the checks' DMN definition.

Notes

• The Description should already be available in the OpenAPI JSON and therefore importable via the existing bin/library/sync-metadata script.
• Relates to Documentation for Library Checks #341. (This is just something that is immediately actionable)