Mark relevant tests synchronous

One of the things we do during the tests is change the config. But that's global state and different tests were interfering.
E.g. one test would set `clear_config([:instance, :admin_privileges], [:statuses_read])`, but while that runs, another test may
do `clear_config([:instance, :admin_privileges], [:user_invite])`. Now the code for the first test checks the setting, and it
finds `:user_invite` instead of `:statuses_read`.

Now the modules where this happens are marked to run synchronously, so they don't interfere with each other.

test/pleroma/web/admin_api/controllers/admin_api_controller_test.exs

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.AdminAPI.AdminAPIControllerTest do
-  use Pleroma.Web.ConnCase
+  use Pleroma.Web.ConnCase, async: false
   use Oban.Testing, repo: Pleroma.Repo
 
   import ExUnit.CaptureLog

test/pleroma/web/admin_api/controllers/chat_controller_test.exs

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.AdminAPI.ChatControllerTest do
-  use Pleroma.Web.ConnCase, async: true
+  use Pleroma.Web.ConnCase, async: false
 
   import Pleroma.Factory
 

test/pleroma/web/admin_api/controllers/invite_controller_test.exs

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.AdminAPI.InviteControllerTest do
-  use Pleroma.Web.ConnCase, async: true
+  use Pleroma.Web.ConnCase, async: false
 
   import Pleroma.Factory
 

test/pleroma/web/admin_api/controllers/report_controller_test.exs

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.AdminAPI.ReportControllerTest do
-  use Pleroma.Web.ConnCase, async: true
+  use Pleroma.Web.ConnCase, async: false
 
   import Pleroma.Factory
 

test/pleroma/web/admin_api/controllers/status_controller_test.exs

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.AdminAPI.StatusControllerTest do
-  use Pleroma.Web.ConnCase, async: true
+  use Pleroma.Web.ConnCase, async: false
 
   import Pleroma.Factory
 

test/pleroma/web/admin_api/controllers/user_controller_test.exs

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 defmodule Pleroma.Web.AdminAPI.UserControllerTest do
-  use Pleroma.Web.ConnCase
+  use Pleroma.Web.ConnCase, async: false
   use Oban.Testing, repo: Pleroma.Repo
 
   import Mock