Polish "Add support for Async invocation in a native image"

This registers the hints if the annotation post processor is active,
rather than statically.

See gh-28710

spring-context/src/main/resources/META-INF/spring/aot.factories

@@ -1,5 +1,2 @@
-org.springframework.aot.hint.RuntimeHintsRegistrar= \
-org.springframework.scheduling.annotation.SchedulingRuntimeHints
-
 org.springframework.beans.factory.aot.BeanRegistrationAotProcessor= \
 org.springframework.context.aot.ReflectiveProcessorBeanRegistrationAotProcessor