Micronaut + GraalVM - no compile

**Describe the bug**
Adding the flowable-engine dependency to a Micronaut engine, and instantiate the process engine causes compile failures when trying to make GraalVM native image.

**Expected behavior**
Create a native image using GraalVM.

**Code**
https://github.com/mvniekerk/micronaut-kotlin-graalvm-flowable

**Additional context**
Flowable: 6.4.2

Start with the external reproduction at github.com/mvniekerk/micronaut-kotlin-graalvm-flowable and reproduce the native-image compile failure using Flowable 6.4.2. Record the specific compiler errors and trace them into the Flowable engine integration; done means the Micronaut example builds a native image successfully.

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