HSEARCH-4073 Unnecessary "throws" in EntityReader

Signed-off-by: Yoann Rodière <yoann@hibernate.org>

mapper/orm-batch-jsr352/core/src/main/java/org/hibernate/search/batch/jsr352/core/massindexing/step/lucene/spi/EntityReader.java

@@ -257,7 +257,7 @@ public void close() {
 	 * Read item from database using JPA. Each read, there will be only one entity fetched.
 	 */
 	@Override
-	public Object readItem() throws Exception {
+	public Object readItem() {
 		log.readingEntity();
 
 		Object entity = chunkState.next();