Lint and fix test to match new log message

lib/pleroma/application_requirements.ex

@@ -34,7 +34,8 @@ defmodule Pleroma.ApplicationRequirements do
         "Account activation enabled, but no Mailer settings enabled.\nPlease set config :pleroma, :instance, account_activation_required: false\nOtherwise setup and enable Mailer."
       )
 
-      {:error, "Account activation enabled, but Mailer is disabled. Cannot send confirmation emails."}
+      {:error,
+       "Account activation enabled, but Mailer is disabled. Cannot send confirmation emails."}
     else
       :ok
     end

test/application_requirements_test.exs

@@ -26,7 +26,7 @@ defmodule Pleroma.ApplicationRequirementsTest do
       Pleroma.Config.put([Pleroma.Emails.Mailer, :enabled], false)
 
       assert_raise Pleroma.ApplicationRequirements.VerifyError,
-                   "Confirmation account: Mailer is disabled",
+                   "Account activation enabled, but Mailer is disabled. Cannot send confirmation emails.",
                    fn ->
                      capture_log(&Pleroma.ApplicationRequirements.verify!/0)
                    end