FIX: Show suspended by user (#16927)

- Show "suspended by" user
- Add specs for silence user

spec/requests/admin/users_controller_spec.rb

@@ -162,6 +162,7 @@ RSpec.describe Admin::UsersController do
       expect(user).to be_suspended
       expect(user.suspended_at).to be_present
       expect(user.suspended_till).to be_present
+      expect(user.suspend_record).to be_present
 
       log = UserHistory.where(target_user_id: user.id).order('id desc').first
       expect(log.details).to match(/because I said so/)
@@ -896,6 +897,7 @@ RSpec.describe Admin::UsersController do
       expect(response.status).to eq(200)
       reg_user.reload
       expect(reg_user).to be_silenced
+      expect(reg_user.silenced_record).to be_present
     end
 
     it "can have an associated post" do