batches: refactor to share common elements of workspace lists

Created by: courier-new

Closes #30469 (closed).

This PR refactors the elements that make up the workspaces lists on both the create and execution pages in order to share common styles and a common API. I primarily abstracted out the ListItem and its constituents, not the FilteredConnection pieces, because those are different enough between the two lists that it doesn't make sense to merge them.

Though there are net lines of code added in this PR, the bulk of the additions here are in storybook story coverage, mock data, additional component props Interfaces, and more imports (moving steadily in the direction of 1-component-per-file, which is the frontend platform team's recommendation).

Beyond the refactor, the workspace list design on the execution screen is brought slightly closer in line with the Figma designs (and its preview workspaces list counterpart). I call attention to 2 additional intentional changes with inline comments below.

Test plan

The components this PR touches are all behind a feature flag. More storybook stories have been added to verify changes visually and prevent regressions. I tried to the best of my ability to manually verify the workspace lists behaved as expected.