Remove use of Pulsar ObjectMapperFactory

This commit removes the use of the Pulsar ObjectMapperFactory when
converting the authentication config props map to a JSON string. The
Pulsar factory operates on a shaded returned value of Jackson
ObjectMapper which may not exist when users are using the
non-shaded version of the Pulsar client lib.

See spring-projects/spring-pulsar#562

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/pulsar/PulsarPropertiesMapper.java

@@ -23,14 +23,14 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
+import java.util.stream.Collectors;
 
 import org.apache.pulsar.client.admin.PulsarAdminBuilder;
 import org.apache.pulsar.client.api.ClientBuilder;
 import org.apache.pulsar.client.api.ConsumerBuilder;
 import org.apache.pulsar.client.api.ProducerBuilder;
 import org.apache.pulsar.client.api.PulsarClientException.UnsupportedAuthenticationException;
 import org.apache.pulsar.client.api.ReaderBuilder;
-import org.apache.pulsar.common.util.ObjectMapperFactory;
 
 import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.pulsar.listener.PulsarContainerProperties;
@@ -87,7 +87,10 @@ private void customizeAuthentication(AuthenticationConsumer authentication,
 	private String getAuthenticationParamsJson(Map<String, String> params) {
 		Map<String, String> sortedParams = new TreeMap<>(params);
 		try {
-			return ObjectMapperFactory.create().writeValueAsString(sortedParams);
+			return sortedParams.entrySet()
+				.stream()
+				.map((e) -> "\"%s\":\"%s\"".formatted(e.getKey(), e.getValue()))
+				.collect(Collectors.joining(",", "{", "}"));
 		}
 		catch (Exception ex) {
 			throw new IllegalStateException("Could not convert auth parameters to encoded string", ex);