Fix: superadmin create faq

[max-out-oluwadara]

Fixes Issue/Linear Ticket

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• Linear Ticket Example: Fixes ID-#{ISSUE}

Changes proposed

Added logic to check for duplicate FAQ entries in the database. Updated createFaq method in FAQService to ensure unique FAQ questions. Handled QueryFailedError for database operations.

The response body should be:

 {
  "status_code": 201,
  "message": "FAQ created successfully",
  "data": {
    "question": "What is the return policy?",
    "answer": "Our return policy allows returns within 30 days of purchase.",
    "category": "Policies",
    "id": "2dea5fe9-c635-4e6e-a059-ef3836b20661",
    "created_at": "2024-08-09T20:07:53.285Z",
    "updated_at": "2024-08-09T20:07:53.285Z"
  }
}

also the error message match

{
  "status_code": Error Code,
  "message": "Error Message",
  "data": {}
}

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