Fix Oban warning

Warning example:

     [warn] Expected Elixir.Pleroma.Workers.BackgroundWorker.perform/2 to return :ok, {:ok, value}, or {:error, reason}. Instead received:  [error: "not found @user@server.party", error: "not found "]  The job will be considered a success.

lib/pleroma/workers/background_worker.ex

@@ -35,7 +35,7 @@ def perform(
         _job
       ) do
     blocker = User.get_cached_by_id(blocker_id)
-    User.perform(:blocks_import, blocker, blocked_identifiers)
+    {:ok, User.perform(:blocks_import, blocker, blocked_identifiers)}
   end
 
   def perform(
@@ -47,7 +47,7 @@ def perform(
         _job
       ) do
     follower = User.get_cached_by_id(follower_id)
-    User.perform(:follow_import, follower, followed_identifiers)
+    {:ok, User.perform(:follow_import, follower, followed_identifiers)}
   end
 
   def perform(%{"op" => "media_proxy_preload", "message" => message}, _job) do

test/user_test.exs

@@ -756,8 +756,8 @@ test "it imports user followings from list" do
       ]
 
       {:ok, job} = User.follow_import(user1, identifiers)
-      result = ObanHelpers.perform(job)
 
+      assert {:ok, result} = ObanHelpers.perform(job)
       assert is_list(result)
       assert result == [user2, user3]
     end
@@ -979,8 +979,8 @@ test "it imports user blocks from list" do
       ]
 
       {:ok, job} = User.blocks_import(user1, identifiers)
-      result = ObanHelpers.perform(job)
 
+      assert {:ok, result} = ObanHelpers.perform(job)
       assert is_list(result)
       assert result == [user2, user3]
     end

test/web/twitter_api/util_controller_test.exs

@@ -116,7 +116,7 @@ test "it imports follows with different nickname variations", %{conn: conn} do
         |> json_response(:ok)
 
       assert response == "job started"
-      assert [job_result] = ObanHelpers.perform_all()
+      assert [{:ok, job_result}] = ObanHelpers.perform_all()
       assert job_result == [user2, user3, user4, user5, user6]
     end
   end
@@ -180,7 +180,7 @@ test "it imports blocks with different nickname variations", %{conn: conn} do
         |> json_response(:ok)
 
       assert response == "job started"
-      assert [job_result] = ObanHelpers.perform_all()
+      assert [{:ok, job_result}] = ObanHelpers.perform_all()
       assert job_result == [user2, user3, user4, user5, user6]
     end
   end