Changes to Get all web search providers

added the non-success response with the status 400

added the non-success response with the status 500

added the new brave enum value to the providers/items/provider response property for the response status 200

added the new crawl4ai enum value to the providers/items/provider response property for the response status 200

added the new firecrawl enum value to the providers/items/provider response property for the response status 200

added the new searxng enum value to the providers/items/provider response property for the response status 200

added the new optional query request parameter reveal

added the optional property error/requestId to the response with the 401 status

added the optional property error/requestId to the response with the 403 status

endpoint added