Fix CI failure in energy module caused by :energy:compileTestGroovy StackOverflowError

[wborn]

Summary

The CI job for PR #55 fails in the energy module during Groovy test compilation with a java.lang.StackOverflowError.

Job: https://github.com/openremote/extensions/actions/runs/29480690522/job/87563501825?pr=55

Failure details

• Failing task: :energy:compileTestGroovy
• Error: java.lang.StackOverflowError
• Workflow runs ./gradlew build in CI under JDK 21
• Earlier test output in the same log shows tests completing successfully, so the failure appears to be in build configuration / Groovy compilation rather than test logic