GH-2135: Fix array support for mappings

See #2135.

Fix NullPointerException, that is thrown when configuring arrays for JsonDeserializer.TYPE_MAPPINGS.

Author: m-ibot

Diff for: spring-kafka/src/main/java/org/springframework/kafka/support/serializer/JsonDeserializer.java

@@ -531,8 +531,9 @@ public synchronized void addTrustedPackages(String... packages) {
 
 	private void addMappingsToTrusted(Map<String, Class<?>> mappings) {
 		mappings.values().forEach(clazz -> {
-			doAddTrustedPackages(clazz.getPackage().getName());
-			doAddTrustedPackages(clazz.getPackage().getName() + ".*");
+			String packageName = clazz.isArray() ? clazz.getComponentType().getPackage().getName() : clazz.getPackage().getName();
+			doAddTrustedPackages(packageName);
+			doAddTrustedPackages(packageName + ".*");
 		});
 	}