Block non-localhost requests for all tests

Only blocking them for the system tests didn't actually
work anyway as the setting is global so would apply to all
tests after the first system test.

test/application_system_test_case.rb

@@ -1,8 +1,6 @@
 require "test_helper"
 require "capybara/poltergeist"
 
-WebMock.disable_net_connect!(:allow_localhost => true)
-
 # Work around weird debian/ubuntu phantomjs
 # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=817277
 # https://github.com/ariya/phantomjs/issues/14376

test/test_helper.rb

@@ -6,6 +6,8 @@ require_relative "../config/environment"
 require "rails/test_help"
 require "webmock/minitest"
 
+WebMock.disable_net_connect!(:allow_localhost => true)
+
 module ActiveSupport
   class TestCase
     include FactoryBot::Syntax::Methods