Add 'array' return type in Drupal\entity\EventSubscriber\EntityDuplicateSubscriber

Looking at the pipelines for Entity API there are no errors shown for this at Next Major, so maybe the test coverage does not include this event subscriber?

I will create a MR for the oneline change, and then see if I can include it in Scheduler testing, to demonstrate the fix.

That worked nicely. I added this MR via the composer file, in https://git.drupalcode.org/project/scheduler/-/merge_requests/161/diffs?commit_id=7755a07dca9ce2d917188be0e1a2d6dadabd4fb9

Before
https://git.drupalcode.org/project/scheduler/-/jobs/2301653
Search for "EntityDuplicateSubscriber" and see 24 occcurences of the error

After
https://git.drupalcode.org/project/scheduler/-/jobs/2311391
No text "EntityDuplicateSubscriber" because that error is fixed.

Quite straightforward ~~ Marking this one RTBC to move things ahead.

Thanks. I'm using this MR branch in a temporary swapped-in composer.json for D11 testing. When the change is committed, I should be able to alter the dependency from
"drupal/entity": "dev-3465393-EntityDuplicateSubscriber-array-return as 1.0",
to just
"drupal/entity": "dev-1.x as 1.0",

Merged.

Automatically closed - issue fixed for 2 weeks with no activity.