List `/embed` and `/export` URLs do not work if list title slug is missing

The paths for embedding and exporting lists are generally defined as follows:
Exports: `/people/{username}/lists/{list_olid}/export`
Embed: `/people/{username}/lists/{list_olid}/embed`

Navigating to either of these URLs redirects to the list page, with `export` or `embed` being replaced with the list's name (URL encoded).

The links work correctly if the encoded list name is included in the URL:
Exports: `/people/{username}/lists/{list_olid}/{list_name}/export`
Embed: `/people/{username}/lists/{list_olid}/{list_name}/embed`

### Evidence / Screenshot (if possible)

### Relevant url?

https://openlibrary.org/people/jachamp/lists/OL201547L/export?format=json ([archived](https://web.archive.org/web/20220315201138/https://openlibrary.org/people/jachamp/lists/OL201547L/Why_am_I_here?format=json))

### Steps to Reproduce

1. Navigate to the JSON export link listed above.

* Actual: Redirected to the list page.
* Expected: Served a JSON representation of the list.

### Details

- **Logged in (Y/N)?** N/A
- **Browser type/version?** N/A
- **Operating system?** N/A
- **Environment (prod/dev/local)?** prod

### Proposal & Constraints

I'm not even sure if this is a bug. The export links on list pages use the longer, properly working, URLs. I didn't see any embed links on the page.

If the current behavior is expected, we should, at the very least, add some documentation about the routing. How and where are the controllers' path definitions being overwritten (if that's what is happening)? Are other controller's paths misleading?

### Related files

/openlibrary/plugins/openlibrary/lists.py:
https://github.com/internetarchive/openlibrary/blob/f4b2f8f4aebaae550f44feecaf22b3f75aac64a5/openlibrary/plugins/openlibrary/lists.py#L447-#L483

### Stakeholders