So restarting IntelliJ this morning solved the issue! A mystery but there we go.
However, I was still getting the same failure when running the unit tests. I ended adding the following code to a Spring configuration class we use to setup our tests, which solved the problem and am able to run unit tests against the EE version of Camunda.
@Bean
public CamundaBpmProperties camundaBpmProperties() {
return new CamundaBpmProperties();
}