A quick followup PR for the merged #11767, removing an unused class.

[landreev]

What this PR does / why we need it:

This is a trivial change, removing a class that was deprecated and no longer in use. It can be considered cosmetic.
I simply missed @stevenwinship's comments the other day pointing out that the unused code was still there.

Which issue(s) this PR closes:

does not by itself close any issues

Special notes for your reviewer:

Suggestions on how to test this:

copy-and-pasting what I said in the original #11767:

I don't think there's a way to test this simple interface change by itself. This is an auxiliary PR that needs to be merged (and published) before I can make the main PR for #11405. Once that PR is made, the overall testing and QA will happen there.

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

Is there a release notes update needed for this change?:

Additional documentation:

[coveralls]

coverage: 23.778%. remained the same
when pulling ad764e9 on 11766-new-io.gdcc.dataverse-spi
into 53bff4c on develop.

[ofahimIQSS]

[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:07 min
[INFO] Finished at: 2025-10-24T14:20:12Z
[INFO] ------------------------------------------------------------------------
Error: Failed to execute goal org.sonatype.plugins:nexus-staging-maven-plugin:1.6.13:deploy (injected-nexus-deploy) on project dataverse-spi: Failed to deploy artifacts: Could not transfer artifact io.gdcc:dataverse-spi:jar:2.1.0-PR11906-20251024.141904-1 from/to central (https://central.sonatype.com/repository/maven-snapshots/): status code: 401, reason phrase: Unauthorized (401) -> [Help 1]
Error:
Error: To see the full stack trace of the errors, re-run Maven with the -e switch.
Error: Re-run Maven using the -X switch to enable full debug logging.
Error:
Error: For more information about the errors and possible solutions, please read the following articles:
Error: [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
Error: Process completed with exit code 1.

Seeing this ^

[pdurbin]

@ofahimIQSS I would suggest updating the branch.

[landreev]

Can we merge this thing? Automatic publishing of the snapshot is still failing. But @pdurbin and I are working on this separately. There are no new, or functional changes in the PR, we are simply removing some unused code. But it would be preferable to have it merged before we (manually) publish the spi on mvn central.