mod actions: hide ip bans from non-mods.

Hide IP ban creation and deletion actions from non-mods in the
/mod_actions listing.

The previous approach of just filtering out the IP from the description
was hacky and didn't work with the `only` param (/mod_actions.json?only=id
still included the description field).

test/unit/mod_action_test.rb

@@ -3,17 +3,15 @@ require 'test_helper'
 class ModActionTest < ActiveSupport::TestCase
   context "A mod action" do
     setup do
-      @user = FactoryBot.create(:user)
-      CurrentUser.user = @user
-      CurrentUser.ip_addr = "127.0.0.1"
+      @user = create(:user)
+      @mod = create(:moderator_user)
     end
 
     should "hide ip addresses from non-moderators in ip ban modactions" do
-      FactoryBot.create(:ip_ban, ip_addr: "1.1.1.1", reason: "test")
+      as(@mod) { create(:ip_ban, ip_addr: "1.1.1.1", reason: "test") }
 
-      assert_equal(1, ModAction.count)
-      assert_equal("#{@user.name} created ip ban", ModAction.last.filtered_description)
-      assert_equal("#{@user.name} created ip ban", ModAction.last.as_json["description"])
+      as(@user) { assert_equal(0, ModAction.search({}).count) }
+      as(@mod) { assert_equal(1, ModAction.search({}).count) }
     end
   end
 end