Remove nullable annotation in IndexShard constructor (#80468)

Author: mushao999

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -300,7 +300,7 @@ public IndexShard(
         final IndexCache indexCache,
         final MapperService mapperService,
         final SimilarityService similarityService,
-        final @Nullable EngineFactory engineFactory,
+        final EngineFactory engineFactory,
         final IndexEventListener indexEventListener,
         final CheckedFunction<DirectoryReader, DirectoryReader, IOException> indexReaderWrapper,
         final ThreadPool threadPool,