Exposing gRPC test server port should backoff if gRPC is not present

[nealeu]

Direct upgrade from 4.0.6 results in some GRPC features being enabled despite no active choice or the relevant classes being available:

The following exception is encountered via GrpcPortInfoApplicationContextInitializer in spring-boot-grpc-test.

Caused by: java.lang.TypeNotPresentException: Type org.springframework.grpc.server.lifecycle.GrpcServerStartedEvent not present
	at java.base/java.lang.Class.getGenericInterfaces(Class.java:1278)
	at org.springframework.core.ResolvableType.getInterfaces(ResolvableType.java:544)
	at org.springframework.core.ResolvableType.as(ResolvableType.java:492)
	at org.springframework.context.event.GenericApplicationListenerAdapter.resolveDeclaredEventType(GenericApplicationListenerAdapter.java:112)

Given the involvment of spring-boot-starter-test-classic, I suspect this is that this was added to the -classic module dependencies, which has resulted in a "Gotcha!".

Workaround

Exclude spring-boot-grpc-test or migrate from using -classic dependencies.

Possible fix

Revert addition of grpc to classic jars, or update release notes to point out the gotcha of using classic wrt addition of grpc.