[Java][jaxrs-spec] Fix generated `JsonTypeName` when using underscore in schema names #809

Job	Run time
Build JAX-RS (samples/server/petstore/jaxrs-datelib-j8)	43s
Build JAX-RS (samples/server/petstore/jaxrs-resteasy/default)	47s
Build JAX-RS (samples/server/petstore/jaxrs-spec-withxml)	48s
Build JAX-RS (samples/server/petstore/jaxrs/jersey2)	57s
Build JAX-RS (samples/server/petstore/jaxrs-spec)	46s
Build JAX-RS (samples/server/petstore/jaxrs-resteasy/eap-java8)	45s
Build JAX-RS (samples/server/petstore/jaxrs-jersey)	57s
Build JAX-RS (samples/server/petstore/jaxrs-spec-interface-response)	46s
Build JAX-RS (samples/server/petstore/jaxrs-resteasy/eap-joda)	1m 0s
Build JAX-RS (samples/server/petstore/jaxrs-resteasy/eap)	57s
Build JAX-RS (samples/server/petstore/jaxrs/jersey2-useTags)	53s
Build JAX-RS (samples/server/petstore/jaxrs-spec-interface)	46s
Build JAX-RS (samples/server/petstore/jaxrs-spec-microprofile-openapi-annotations)	55s
Build JAX-RS (samples/server/petstore/jaxrs-resteasy/joda)	1m 2s
Build JAX-RS (samples/server/petstore/jaxrs-cxf-cdi)	53s
Build JAX-RS (samples/server/petstore/jaxrs-cxf-annotated-base-path)	51s
Build JAX-RS (samples/server/petstore/jaxrs-cxf-non-spring-app)	50s
Build JAX-RS (samples/server/petstore/jaxrs-spec-swagger-annotations)	51s
Build JAX-RS (samples/server/petstore/jaxrs-spec-swagger-v3-annotations)	38s
Build JAX-RS (samples/server/petstore/jaxrs-spec-swagger-v3-annotations-jakarta)	36s
Build JAX-RS (samples/server/petstore/jaxrs-cxf)	54s
	17m 35s

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