Chore: API Improvements (#2956)

- API to fetch info of a single inbox
- Document passing custom_attributes in the API
- Ability to filter contacts with contact identifier in search API

app/controllers/api/v1/accounts/inboxes_controller.rb

@@ -1,12 +1,15 @@
 class Api::V1::Accounts::InboxesController < Api::V1::Accounts::BaseController
   before_action :fetch_inbox, except: [:index, :create]
   before_action :fetch_agent_bot, only: [:set_agent_bot]
-  before_action :check_authorization
+  # we are already handling the authorization in fetch inbox
+  before_action :check_authorization, except: [:show]
 
   def index
     @inboxes = policy_scope(Current.account.inboxes.order_by_name.includes(:channel, { avatar_attachment: [:blob] }))
   end
 
+  def show; end
+
   def assignable_agents
     @assignable_agents = (Current.account.users.where(id: @inbox.members.select(:user_id)) + Current.account.administrators).uniq
   end