Chore: Refactor round robin logic (#1015)

Co-authored-by: Pranav Raj S <pranav@thoughtwoot.com>

app/services/round_robin/assignment_service.rb

@@ -0,0 +1,24 @@
+class RoundRobin::AssignmentService
+  pattr_initialize [:conversation]
+
+  def perform
+    # online agents will get priority
+    new_assignee = round_robin_manage_service.available_agent(priority_list: online_agents)
+    conversation.update(assignee: new_assignee) if new_assignee
+  end
+
+  private
+
+  def online_agents
+    online_agents = OnlineStatusTracker.get_available_users(conversation.account_id)
+    online_agents.select { |_key, value| value.eql?('online') }.keys if online_agents.present?
+  end
+
+  def round_robin_manage_service
+    @round_robin_manage_service ||= RoundRobin::ManageService.new(inbox: conversation.inbox)
+  end
+
+  def round_robin_key
+    format(::Redis::Alfred::ROUND_ROBIN_AGENTS, inbox_id: conversation.inbox_id)
+  end
+end