feat: (AI-302) Adding changes for summarize_on_end and also adding a new route…

[vinya-jag]

… for summary

Description

Following changes have been added for AI-302:

• Created a new route to GET /sessions/{session_id}/summary
  "Fetch summary of transcripts for a session"
• Edited current Create/ Update and Get Meetings for summarize_on_end flag
• Verified on Swagger Docs for errors and corrected them
• Verified on 'npm run dev' for correctness.

Resolved issues

Closes #1 AI-302

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