feat(backend): get rid of unused hibernate dependency

[anna-parker]

@tombch and I were looking into the exposed ORM and I realized we have a dependency for a different ORM hibernate that appears unused in the code - I now checked that the preview is healthy, so I would remove the dependency.

resolves #

Screenshot

PR Checklist

• All necessary documentation has been adapted.
• The implemented feature is covered by appropriate, automated tests.
• Any manual testing that has been done is documented (i.e. what exactly was tested?)

🚀 Preview: https://remove-hibernate.loculus.org

[claude]

Claude finished @anna-parker's task in 1m 43s —— View job

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Code Review

• Read the changed file
• Verify hibernate is truly unused in the codebase
• Provide review feedback

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The change removes implementation "org.hibernate.validator:hibernate-validator" from build.gradle.

Verdict: LGTM with one minor note.

The explicit declaration is redundant — gradle.lockfile still contains org.hibernate.validator:hibernate-validator:8.0.3.Final across all configurations, confirming it remains on the classpath via a transitive dependency (likely from springdoc-openapi-starter-webmvc-ui or another Spring Boot starter). No functionality is broken.

One small thing worth noting: the PR description calls this "unused", but hibernate-validator is the runtime implementation of the Jakarta Bean Validation API. The backend does use validation annotations (@Valid, @Max, custom ConstraintValidator implementations in SubmissionController, Organism.kt, etc.) that depend on it at runtime. The explicit declaration is redundant (not unused). A minor wording distinction, but it could mislead a future reader into thinking the validation feature itself isn't needed.

No tests or documentation changes are needed for a dependency declaration cleanup like this.