`NoClassDefFoundError` when processing reflection hints for `PageModule`

[christophstrobl]

We need to guard the hint for Unpaged in WebRuntimeHints so it is only triggered if jackson is present.

Exception in thread "main" java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/module/SimpleModule
...
at org.springframework.data.web.aot.WebRuntimeHints.lambda$registerHints$0(WebRuntimeHints.java:36)	
	at org.springframework.aot.hint.ReflectionHints.registerType(ReflectionHints.java:88)	
	at org.springframework.data.web.aot.WebRuntimeHints.registerHints(WebRuntimeHints.java:35)	
	at org.springframework.context.aot.RuntimeHintsBeanFactoryInitializationAotProcessor$RuntimeHintsRegistrarContribution.lambda$applyTo$0(RuntimeHintsBeanFactoryInitializationAotProcessor.java:116)	
	at java.base/java.util.LinkedHashMap$LinkedValues.forEach(LinkedHashMap.java:647)