chore: Centralize outgoing message reply restrictions for all the channels (#11279)

spec/models/channel/twilio_sms_spec.rb

@@ -3,28 +3,6 @@
 require 'rails_helper'
 
 RSpec.describe Channel::TwilioSms do
-  describe '#has_24_hour_messaging_window?' do
-    context 'with medium whatsapp' do
-      let!(:whatsapp_channel) { create(:channel_twilio_sms, medium: :whatsapp) }
-
-      it 'returns true' do
-        expect(whatsapp_channel.messaging_window_enabled?).to be true
-        expect(whatsapp_channel.name).to eq 'Whatsapp'
-        expect(whatsapp_channel.medium).to eq 'whatsapp'
-      end
-    end
-
-    context 'with medium sms' do
-      let!(:sms_channel) { create(:channel_twilio_sms, medium: :sms) }
-
-      it 'returns false' do
-        expect(sms_channel.messaging_window_enabled?).to be false
-        expect(sms_channel.name).to eq 'Twilio SMS'
-        expect(sms_channel.medium).to eq 'sms'
-      end
-    end
-  end
-
   describe '#validations' do
     context 'with phone number blank' do
       let!(:sms_channel) { create(:channel_twilio_sms, medium: :sms, phone_number: nil) }