Chore: Remove unnessecary check if object exists (#480)

app/controllers/api/v1/inbox_members_controller.rb

@@ -4,18 +4,12 @@ class Api::V1::InboxMembersController < Api::BaseController
 
   def create
     # update also done via same action
-    if @inbox
-      begin
     update_agents_list
     head :ok
   rescue StandardError => e
     Rails.logger.debug "Rescued: #{e.inspect}"
     render_could_not_create_error('Could not add agents to inbox')
   end
-    else
-      render_not_found_error('Agents or inbox not found')
-    end
-  end
 
   def show
     @agents = current_account.users.where(id: @inbox.members.pluck(:user_id))