chore: clear Twilio number webhooks during teardown

enterprise/app/services/twilio/voice_teardown_service.rb

@@ -3,6 +3,7 @@ class Twilio::VoiceTeardownService
 
   def perform
     delete_twiml_app if channel.twiml_app_sid.present?
+    clear_number_webhooks
   rescue StandardError => e
     Rails.logger.error("TWILIO_VOICE_TEARDOWN_ERROR: #{e.class} #{e.message} phone=#{channel.phone_number} account=#{channel.account_id}")
   ensure
@@ -15,6 +16,17 @@ class Twilio::VoiceTeardownService
     twilio_client.applications(channel.twiml_app_sid).delete
   end
 
+  def clear_number_webhooks
+    numbers = twilio_client.incoming_phone_numbers.list(phone_number: channel.phone_number)
+    return if numbers.empty?
+
+    twilio_client
+      .incoming_phone_numbers(numbers.first.sid)
+      .update(voice_url: '', status_callback: '')
+  rescue StandardError => e
+    Rails.logger.error("TWILIO_VOICE_TEARDOWN_WEBHOOK_ERROR: #{e.class} #{e.message} phone=#{channel.phone_number} account=#{channel.account_id}")
+  end
+
   def clear_voice_credentials
     channel.update(twiml_app_sid: nil)
   end