Delete report notifs when demoting from superuser

When someone isn't a superuser any more, they shouldn't see the reporsts any more either.
Here we delete the report notifications from a user when that user gets updated from being a superuser to a non-superuser.

lib/pleroma/notification.ex

@@ -341,6 +341,14 @@ defmodule Pleroma.Notification do
     |> Repo.delete_all()
   end
 
+  def destroy_multiple_from_types(%{id: user_id}, types) do
+    from(n in Notification,
+      where: n.user_id == ^user_id,
+      where: n.type in ^types
+    )
+    |> Repo.delete_all()
+  end
+
   def dismiss(%Pleroma.Activity{} = activity) do
     Notification
     |> where([n], n.activity_id == ^activity.id)

lib/pleroma/user.ex

@@ -1127,10 +1127,27 @@ defmodule Pleroma.User do
     |> update_and_set_cache()
   end
 
-  def update_and_set_cache(changeset) do
+  def update_and_set_cache(%{data: %Pleroma.User{} = user} = changeset) do
+    was_superuser_before_update = User.superuser?(user)
+
     with {:ok, user} <- Repo.update(changeset, stale_error_field: :id) do
       set_cache(user)
     end
+    |> maybe_remove_report_notifications(was_superuser_before_update)
+  end
+
+  defp maybe_remove_report_notifications(
+         {:ok, %Pleroma.User{} = user} = result,
+         was_superuser_before_update
+       ) do
+    if was_superuser_before_update and not User.superuser?(user),
+      do: user |> Notification.destroy_multiple_from_types(["pleroma:report"])
+
+    result
+  end
+
+  defp maybe_remove_report_notifications(result, _) do
+    result
   end
 
   def get_user_friends_ap_ids(user) do