feat: add ongoing prop to block highlight

[dianneweinthal]

adds ongoing prop and removes date clip for block highlight list to improve display on exhibitions and series https://deploy-preview-311--ucla-library-storybook.netlify.app/?path=/story/block-highlight--list-ongoing

[github-actions[bot]]

Percy Screenshots

In order to conserve our percy screenshot allowance, percy is not configured to run automatically. Please make sure the PR is ready and all other checks are passing, then start it manually:

1. Visit https://github.com/UCLALibrary/ucla-library-website-components/actions/workflows/percy.yml 2. Click the 'Run workflow' button in the blue bar. 3. Select the correct branch for this PR and click 'Run workflow' again to confirm.

[github-actions[bot]]

🚀 Deployed on https://deploy-preview-311--ucla-library-storybook.netlify.app

[pghorpade]

:tada: This PR is included in version 2.28.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: