Search: don't return unpublished albums and images from unpublished albums

[deanmoses]

Search currently returns unpublished albums and images in those albums. That's a bug; those results will be unclickable by non-admins.

Implementation Notes

To not return images from unpublished albums, the lambda that receives the Redis search results would have to bulk retrieve all the albums for the images in order to check their publish status.

I rejected an alternative implementation, which was to not index images from unpublished albums. But when the album IS published, DynamoDB won't re-stream those images because they aren't changed, which means they'll never get indexed. Since we do all edits BEFORE publishing the album, no image would ever get indexed.

I'm okay leaving this bug for now, given that search is unlikely to return a result in the latest album, and the consequence of doing so is just an unclickable search result.