DEV: `S3Inventory#unsorted_files` should always return an array (#8034)

DEV: S3Inventory#unsorted_files should always return an array (#8034)

diff --git a/lib/s3_inventory.rb b/lib/s3_inventory.rb
index b69f4a0..b98e2e9 100644
--- a/lib/s3_inventory.rb
+++ b/lib/s3_inventory.rb
@@ -265,6 +265,7 @@ class S3Inventory
     objects
   rescue Aws::Errors::ServiceError => e
     log("Failed to list inventory from S3", e)
+    []
   end
 
   def inventory_id

GitHub sha: 68708db7