When a post with a subject is collapsed, hide its attachments.

Currently, attachments will appear in the timeline even if a post is collapsed.

This hides them when the post is collapsed and reveals them when the post is expanded.

If the attachment is marked NSFW, the NSFW clickthrough will still be there won't be there if collapse subjects is on.

I did this because I noticed I wasn't realising that posts with subjects and attachments had post bodies that I could read, because my brain thought that since I could see the attachments, I must be looking at the full post.

This frees up more space in a timeline when a user collapses a post, because there won't be big image blocks there.

Before (collapsed)

After (collapsed)

Expanded (except imagine no NSFW clickthrough)