feat: Line Channel (#2904)

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

fixes: #2738

app/models/channel/api.rb

@@ -18,22 +18,15 @@
 #
 
 class Channel::Api < ApplicationRecord
+  include Channelable
+
   self.table_name = 'channel_api'
   EDITABLE_ATTRS = [:webhook_url].freeze
 
-  validates :account_id, presence: true
-  belongs_to :account
-
   has_secure_token :identifier
   has_secure_token :hmac_token
 
-  has_one :inbox, as: :channel, dependent: :destroy
-
   def name
     'API'
   end
-
-  def has_24_hour_messaging_window?
-    false
-  end
 end