Imports via ISBN searches create duplicate works

When a user searches by ISBN and the edition is not already present in the catalog, the edition is imported. However, this frequently creates a new work when an appropriate work already exists.

### Evidence / Screenshot (if possible)

### Relevant url?
https://openlibrary.org/books/OL28122354M/The_Hound_of_the_Baskervilles (imported edition)
https://openlibrary.org/works/OL20779126W/The_Hound_of_the_Baskervilles (created work)
This import should have been associated with https://openlibrary.org/works/OL262454W/The_Hound_of_the_Baskervilles

### Steps to Reproduce

1. Search for an ISBN that does not exist in the Open Library catalog, but exists on amazon and has a corresponding work on Open Library.
2. If imported, check to see if a new work (duplicate) was created or if the edition is associated with the existing work. (I've experienced both cases.)

* Actual: Sometimes the import creates a new work when an appropriate work already exists.
* Expected: If an appropriate work exists, the import should not create a new work.

### Details

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### Proposal & Constraints

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### Stakeholders

@mekarpeles @cdrini