docs: Fix docs publish CI failing on main

[BalduinLandolt]

Pull Request Checklist

Task Description/Number

Docs publish CI failed on main because the OpenAPI docs are not present - as they need to be generated.
This requires a bit of setup (java, just, ...).

PR Type

• build/chore: maintenance tasks (no production code change)
• docs: documentation changes (no production code change)
• feat: represents new features
• fix: represents bug fixes
• perf: performance improvements
• refactor: represents production code refactoring
• test: adding or refactoring tests (no production code change)
• deprecated: Deprecation warning (ideally referencing a migration guide)

Basic requirements for bug fixes and features

• Tests for the changes have been added
• Docs have been added / updated

Does this PR introduce a breaking change?

• Yes