Fix NPE in ClusterInfoService (#65654) (#65659)

Store stats can be `null` if e.g. the shard was already closed
when the stats where retrieved. Don't record those shards in the
sizes map to fix an NPE in this case.

Author: original-brownbear

server/src/main/java/org/elasticsearch/cluster/InternalClusterInfoService.java

@@ -331,6 +331,9 @@ static void buildShardLevelInfo(Logger logger, ShardStats[] stats, ImmutableOpen
             newShardRoutingToDataPath.put(shardRouting, s.getDataPath());
 
             final StoreStats storeStats = s.getStats().getStore();
+            if (storeStats == null) {
+                continue;
+            }
             final long size = storeStats.sizeInBytes();
             final long reserved = storeStats.getReservedSize().getBytes();