Hartigan

Hi I think I found root cause of problem. I created test which reproduce problem. I found what error occurs when `circuitBreakerConfig.isAutomaticTransitionFromOpenToHalfOpenEnabled()` enabled. If transition from `OPEN` to `HALF_OPEN` state...

I created [pull request](https://github.com/resilience4j/resilience4j/pull/2072) with fix. Also I removed unnecessary `synchronized`.

I found what we cannot remove `synchronized` because of [this code](https://github.com/resilience4j/resilience4j/blob/12f66a31d7b4619ed0ffd1fddee9da683c41b9b7/resilience4j-circuitbreaker/src/main/java/io/github/resilience4j/circuitbreaker/internal/CircuitBreakerStateMachine.java#L737). Pull request already updated