private static Stream<String> nullEleCodeKeys() {
        return Stream.of("httpMethodEnums", "operatorEnums", "paramTypeEnums", "pluginTypeEnums", "rpcTypeEnums",
                "serializeEnums", "redisModeEnums");
    }
test element support.

@param key element key
shenyu-admin/src/test/java/org/apache/shenyu/admin/service/EnumServiceTest.java