test: demonstrate error with bulk update on manual action (#1204)

The following error is produced

1) test manual updates are supported (Ash.Test.Actions.BulkUpdateTest)
     test/actions/bulk/bulk_update_test.exs:358
     ** (CaseClauseError) no case clause matching: nil
     code: |> Ash.bulk_update!(:update_manual, %{},
     stacktrace:
       (ash 3.0.7) lib/ash/actions/update/bulk.ex:2076: anonymous fn/11 in Ash.Actions.Update.Bulk.run_batch/10
       (elixir 1.16.2) lib/enum.ex:1264: anonymous fn/3 in Enum.flat_map/2
       (stdlib 5.0.2) maps.erl:416: :maps.fold_1/4
       (elixir 1.16.2) lib/enum.ex:2540: Enum.flat_map/2
       (ash 3.0.7) lib/ash/actions/update/bulk.ex:1966: Ash.Actions.Update.Bulk.run_batch/10
       (ash 3.0.7) lib/ash/actions/update/bulk.ex:1505: Ash.Actions.Update.Bulk.do_handle_batch/13
       (ash 3.0.7) lib/ash/actions/update/bulk.ex:1042: anonymous fn/12 in Ash.Actions.Update.Bulk.do_stream_batches/7
       (elixir 1.16.2) lib/stream.ex:613: anonymous fn/4 in Stream.map/2
       (elixir 1.16.2) lib/stream.ex:1816: anonymous fn/3 in Enumerable.Stream.reduce/3
       (elixir 1.16.2) lib/stream.ex:273: anonymous fn/4 in Stream.chunk_while_fun/2
       (elixir 1.16.2) lib/stream.ex:1159: anonymous fn/3 in Stream.with_index/2
       (elixir 1.16.2) lib/stream.ex:1079: Stream.do_transform_each/3
       (elixir 1.16.2) lib/stream.ex:1816: anonymous fn/3 in Enumerable.Stream.reduce/3
       (elixir 1.16.2) lib/enum.ex:4839: Enumerable.List.reduce/3
       (elixir 1.16.2) lib/stream.ex:1027: Stream.do_transform_inner_list/7
       (elixir 1.16.2) lib/stream.ex:1828: Enumerable.Stream.do_each/4
       (elixir 1.16.2) lib/stream.ex:1052: Stream.do_transform_inner_enum/7
       (elixir 1.16.2) lib/stream.ex:1828: Enumerable.Stream.do_each/4
       (elixir 1.16.2) lib/stream.ex:943: Stream.do_transform/5
       (elixir 1.16.2) lib/enum.ex:4396: Enum.reverse/1
       (elixir 1.16.2) lib/enum.ex:3728: Enum.to_list/1
       (ash 3.0.7) lib/ash/actions/update/bulk.ex:1070: Ash.Actions.Update.Bulk.run_batches/3
       (ash 3.0.7) lib/ash/actions/update/bulk.ex:386: Ash.Actions.Update.Bulk.run/6
       (ash 3.0.7) lib/ash.ex:2209: Ash.bulk_update!/4
       test/actions/bulk/bulk_update_test.exs:373: (test)

test/actions/bulk/bulk_update_test.exs

@@ -101,6 +101,14 @@ defmodule Ash.Test.Actions.BulkUpdateTest do
     end
   end
 
+  defmodule ManualUpdate do
+    use Ash.Resource.ManualUpdate
+
+    def update(changeset, _opts, _context) do
+      {:ok, changeset.data}
+    end
+  end
+
   defmodule Post do
     @moduledoc false
     use Ash.Resource,
@@ -117,6 +125,10 @@ defmodule Ash.Test.Actions.BulkUpdateTest do
       default_accept :*
       defaults [:read, :destroy, create: :*, update: :*]
 
+      update :update_manual do
+        manual ManualUpdate
+      end
+
       update :update_with_change do
         require_atomic? false
 
@@ -341,6 +353,33 @@ defmodule Ash.Test.Actions.BulkUpdateTest do
                Enum.sort_by(records, & &1.title)
              end)
   end
+
+  test "manual updates are supported" do
+    assert %Ash.BulkResult{
+             records: [
+               %{title: "title1"},
+               %{title: "title2"}
+             ]
+           } =
+             Ash.bulk_create!([%{title: "title1"}, %{title: "title2"}], Post, :create,
+               return_stream?: true,
+               return_records?: true,
+               authorize?: false
+             )
+             |> Stream.map(fn {:ok, result} ->
+               result
+             end)
+             |> Ash.bulk_update!(:update_manual, %{},
+               resource: Post,
+               strategy: :stream,
+               return_records?: true,
+               return_errors?: true,
+               authorize?: false
+             )
+             |> Map.update!(:records, fn records ->
+               Enum.sort_by(records, & &1.title)
+             end)
+  end
 
   test "accepts arguments" do
     assert %Ash.BulkResult{