AdminAPI: hotfix for nil report objects

Backport of: https://git.pleroma.social/pleroma/pleroma/-/merge_requests/3504

CHANGELOG.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - MRF ObjectAgePolicy: Fix pattern matching on "published"
 - TwitterAPI: Make `change_password` and `change_email` require params on body instead of query
 - Subscription(Bell) Notifications: Don't create from Pipeline Ingested replies
+- AdminAPI: Fix rendering reports containing a `nil` object
 
 ## 2.4.0 - 2021-08-08
 

lib/pleroma/web/admin_api/report.ex

@@ -13,7 +13,9 @@ def extract_report_info(
     account = User.get_cached_by_ap_id(account_ap_id)
 
     statuses =
-      Enum.map(status_ap_ids, fn
+      status_ap_ids
+      |> Enum.reject(&is_nil(&1))
+      |> Enum.map(fn
         act when is_map(act) -> Activity.get_by_ap_id_with_object(act["id"])
         act when is_binary(act) -> Activity.get_by_ap_id_with_object(act)
       end)