Fix import path for ResearchManager in app.py

app.py

@@ -1,6 +1,6 @@
 import gradio as gr
 from dotenv import load_dotenv
-from deep_research_agent.research_manager import ResearchManager
+from deep_research_agents.research_manager import ResearchManager
 import sendgrid
 from sendgrid.helpers.mail import Email, Mail, Content, To
 import os