What does this MR do and why?

• Fixes vertical line
• Removes extra system note for threads (and collapse functionality)
  • Why? We don't actually show the Reply option here anyway; you can only get to this state if you select Start a thread instead of Comment. And the collapsed state isn't persisted.
• Fix mobile styles
• On mobile, hides Edit icon button and adds Edit comment option in actions dropdown

What does this MR not do?

• Convert the notes to Vue

Screenshots or screen recordings

Before	After

How to set up and validate locally

Check areas that use our legacy notes:

• Snippet
• Commit
• Are there any others? I thought wiki used them too but I don't actually see a way to comment anywhere on wikis

Links

• ✂️ UX Paper Cuts 16.11 → Snippets & Paper Cuts ... (#425467 - closed)