Thumbnails don't get regenerated after the record is updated

[kirkkwang]

Story

When a record gets created, it take the URI from its preview field and generates thumbnails from it. However, if that fails, #generate_thumbnail isn't triggered on a save/update and therefore even if a Bulkrax roundtripping import is initiated, all it is doing is an update of the existing record so the thumbnail doesn't get generated even though the preview property changes to the correct one.

Acceptance Criteria

• [ ] As a user, I want thumbnails to generate after I update the record through roundtripping

Testing Instructions and Sample Files

• [ ] Have existing data in your application. Do a Bulkrax export of the data (a limit of one record is sufficient)
• [ ] Open the resulting CSV and change the edm:preview field to a different URI (make sure it directly resolves to either a JPG or PDF resource)
• [ ] Initiate a Bulkrax import with the CSV
• [ ] Go to the /sidekiq route and ensure all jobs are completed
• [ ] Observe that thumbnail changed

[ShanaLMoore]

https://congressarchives.slack.com/archives/C048SB2J287/p1699561344353589

[ShanaLMoore]

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