Fix isbn search, matching the regular search

[renatolond]

Description

I noticed on my instance that looking for ISBN directly was always resulting in an "Oops" page. This only happens if the isbn-like search does not have local results (otherwise the local results are displayed).

I tried matching the ISBN results to the regular search results, I guess one method was changed and the other wasn't.

I haven't written any tests, though probably some should be written to avoid this method to get out-of-sync again in the future.

EDIT: looking at the tests, it seems the response expected for this method is quite different than the one that comes back from OL. I don't know if this is because the response changed or if the method being called is incorrect, so I'm not sure on how to go fixing the tests for this one, should a new response be fetched? Should the format of the search be changed to make sure the previous response is fetched?

What type of Pull Request is this?

• Bug Fix
• Enhancement
• Plumbing / Internals / Dependencies
• Refactor

Does this PR change settings or dependencies, or break something?

• This PR changes or adds default settings, configuration, or .env values
• This PR changes or adds dependencies
• This PR introduces other breaking changes

Details of breaking or configuration changes (if any of above checked)

Documentation

• New or amended documentation will be required if this PR is merged
• I have created a matching pull request in the Documentation repository
• I intend to create a matching pull request in the Documentation repository after this PR is merged

Tests

• My changes do not need new tests
• All tests I have added are passing
• I have written tests but need help to make them pass
• I have not written tests and need help to write them