Logged out web UI does not show back button in sidebar

[silverlyne]

Describe the bug
When logged in and navigating content (posts, profiles, etc), a "back" button shows up in the sidebar menu, to the right of the logged in profile image.

When logged out and doing the same thing, the sidebar is not present, so the back button does not show up.

To Reproduce

Steps to reproduce the behavior:

1. Open bsky.app on a web browser in a private window
2. Click one of the posts that shows up in the home feed
3. Verify that the back button does not show up
4. Do this again by clicking on a user profile

Expected behavior

A back button shows up on the sidebar

Screenshots

Details

• Platform: macOS 15.1 beta
• Platform version: Safari 18.1 (20619.2.1)
• App version: Build version: 1.91.1; Bundle info: fb71fff (prod); Bundle date: 24091621; Platform: web
  (App version copied from the logged in tab as build info isnt accessible when logged out)