feat(spring): enable `openApiNullable` with `useJackson3` #1154

Job	Run time
Build with JDK17 (samples/client/petstore/spring-http-interface-reactive)	43s
Build with JDK17 (samples/client/petstore/spring-http-interface-noResponseEntity)	52s
Build with JDK17 (samples/client/petstore/java/microprofile-rest-client-outer-enum)	53s
Build with JDK17 (samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfa...	55s
Build with JDK17 (samples/client/petstore/java/webclient-jakarta)	45s
Build with JDK17 (samples/client/petstore/spring-http-interface)	47s
Build with JDK17 (samples/server/petstore/java-camel/)	1m 2s
Build with JDK17 (samples/server/petstore/java-helidon-server/v3/se)	45s
Build with JDK17 (samples/client/petstore/spring-http-interface-reactive-noResponseEntity)	47s
Build with JDK17 (samples/openapi3/client/petstore/spring-cloud-3)	44s
Build with JDK17 (samples/openapi3/server/petstore/springboot-3)	51s
Build with JDK17 (samples/client/petstore/java-helidon-client/v3/se)	45s
Build with JDK17 (samples/client/petstore/java-helidon-client/v3/mp/)	45s
Build with JDK17 (samples/openapi3/server/petstore/springboot-3-include-http-request-context)	51s
Build with JDK17 (samples/server/petstore/springboot-x-implements-skip)	48s
Build with JDK17 (samples/server/petstore/java-helidon-server/v3/mp/)	52s
	13m 5s

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