Author merge creates search results with "unknown author"

After merging authors, some works are then displayed in search results with "unknown author". Looking at the work details displays the correct author. Clicking the author facet in search results excludes those works that display "unknown author".

### Evidence / Screenshot (if possible)

https://openlibrary.org/search?q=title%3A+%22Jude+the+obscure%22&mode=everything

### Relevant url?

https://openlibrary.org/works/OL24607017W/Jude_the_Obscure

### Steps to Reproduce

1. Go to ...merge an author
2. Do ...check search results to see how books are displayed

* Actual: As described above.
* Expected: When author is merged. All works should display the merged author profile.

### Details

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

### Proposal & Constraints

Maybe solr related?
### Related files

### Stakeholders

@cdrini @mheiman

Start by reproducing the author merge and comparing the search results with the work details for the linked Jude the Obscure example. Trace the search indexing path and verify how merged authors are represented in result displays and facets; done means affected works show the merged author profile and remain included when that author facet is selected.

Written by the indexing model from the issue text.