Update auto-configured ParameterNamesModule to use DEFAULT creator mode

The PROPERTIES creator mode has the unfortunate side-effect of stopping
mixins from working. This commit updates the auto-configured module to
use the DEFAULT creator mode instead.

Closes gh-4336

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration.java

@@ -143,7 +143,7 @@ public class JacksonAutoConfiguration {
 		@Bean
 		@ConditionalOnMissingBean(ParameterNamesModule.class)
 		public ParameterNamesModule parameterNamesModule() {
-			return new ParameterNamesModule(JsonCreator.Mode.PROPERTIES);
+			return new ParameterNamesModule(JsonCreator.Mode.DEFAULT);
 		}
 
 	}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfigurationTests.java

@@ -413,7 +413,7 @@ public class JacksonAutoConfigurationTests {
 
 	@Test
 	public void parameterNamesModuleIsAutoConfigured() {
-		assertParameterNamesModuleCreatorBinding(Mode.PROPERTIES,
+		assertParameterNamesModuleCreatorBinding(Mode.DEFAULT,
 				JacksonAutoConfiguration.class);
 	}