Tests: Remove unneeded explicit cachex use.

Only use cachex when we're actually testing it.

test/pleroma/web/media_proxy/invalidation/http_test.exs

@@ -9,10 +9,6 @@ defmodule Pleroma.Web.MediaProxy.Invalidation.HttpTest do
   import ExUnit.CaptureLog
   import Tesla.Mock
 
-  setup do
-    on_exit(fn -> Cachex.clear(:banned_urls_cache) end)
-  end
-
   test "logs hasn't error message when request is valid" do
     mock(fn
       %{method: :purge, url: "http://example.com/media/example.jpg"} ->

test/pleroma/web/media_proxy/invalidation/script_test.exs

@@ -8,10 +8,6 @@ defmodule Pleroma.Web.MediaProxy.Invalidation.ScriptTest do
 
   import ExUnit.CaptureLog
 
-  setup do
-    on_exit(fn -> Cachex.clear(:banned_urls_cache) end)
-  end
-
   test "it logger error when script not found" do
     assert capture_log(fn ->
              assert Invalidation.Script.purge(

test/pleroma/web/media_proxy/invalidation_test.exs

@@ -15,10 +15,6 @@ defmodule Pleroma.Web.MediaProxy.InvalidationTest do
 
   setup do: clear_config([:media_proxy])
 
-  setup do
-    on_exit(fn -> Cachex.clear(:banned_urls_cache) end)
-  end
-
   describe "Invalidation.Http" do
     test "perform request to clear cache" do
       Config.put([:media_proxy, :enabled], false)

test/pleroma/web/media_proxy/media_proxy_controller_test.exs

@@ -10,10 +10,6 @@ defmodule Pleroma.Web.MediaProxy.MediaProxyControllerTest do
   alias Pleroma.Web.MediaProxy
   alias Plug.Conn
 
-  setup do
-    on_exit(fn -> Cachex.clear(:banned_urls_cache) end)
-  end
-
   describe "Media Proxy" do
     setup do
       clear_config([:media_proxy, :enabled], true)