fix spawners on bukkit

[duplexsystem]

Pull Request

Description

Changelog

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Checklist

Mandatory checks

• [ ] The base branch of this PR is an unreleased version branch (that has a ver/ prefix) or is a branch that is intended to be merged into a version branch.
• [ ] There are no already existing PRs that provide the same changes.
• [ ] The PR is within the scope of Terra (i.e. is something a configurable terrain generator should be doing).
• [ ] Changes follow the code style for this project.
• [ ] I have read the CONTRIBUTING.md document in the root of the git repository.

Types of changes

• [ ] Bug Fix
• [ ] Build system
• [ ] Documentation
• [ ] New Feature
• [ ] Performance
• [ ] Refactoring
• [ ] Repository
• [ ] Revert
• [ ] Style
• [ ] Tests
• [ ] Translation

Compatibility

• [ ] Introduces a breaking change
• [ ] Introduces new functionality in a backwards compatible way.
• [ ] Introduces bug fixes

Documentation

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

Testing

• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

Licensing

• [ ] I am the original author of this code, and I am willing to release it under GPLv3.
• [ ] I am not the original author of this code, but it is in public domain or released under GPLv3 or a compatible license.