batches: introduce SSBC execution status pills

Created by: courier-new

Note: Temporarily based on https://github.com/sourcegraph/sourcegraph/pull/31521 since some changes want the updated page URLs.

Closes https://github.com/sourcegraph/sourcegraph/issues/31166.

Introduces the new double-status pills for the batch changes list page that indicate batch change state as well as latest execution state. Best showcased through the new storybook story.

Additionally, each node on the list will now be a bit smarter about where it takes you when you click on it. If there's an unapplied preview, it will take you to that preview page. If there's an execution in progress or failed, it will take you to that execution page. If it's a draft that's never been executed, it will take you to the editor page.

Definitely recommend reviewing with whitespace changes hidden. The diff without that is confusing.

Test plan

These changes are experimental behind a feature flag and should not impact existing customers, so I only went as far as to verify the intended functionality locally myself. The existing screen stories and snapshots should continue to match the existing behavior.