feat: Telegram Channel (#2901)

- Ability to configure telegram bots as a channel in chatwoot
- Receive a message sent to the telegram bot in chatwoot
- Ability to reply to telegram users from chatwoot
- Receive attachment messages in chatwoot

fixes: #1843

app/models/channel/api.rb

@@ -19,6 +19,7 @@
 
 class Channel::Api < ApplicationRecord
   self.table_name = 'channel_api'
+  EDITABLE_ATTRS = [:webhook_url].freeze
 
   validates :account_id, presence: true
   belongs_to :account