Django REST framework - remove format_suffix_patterns and include_docs_urls

**format_suffix_patterns**

We used DRFs `format_suffix_patterns` helper to allow URLs such as `/api/endpoint.json`. This caused duplicate routes for every endpoint (e.g., `/api/endpoint/` and `/api/endpoint.json`), which led to schema generation warnings about duplicated `operationId` values and unnecessary route complexity. Modern DRF no longer requires these suffixes since content negotiation is handled automatically through the `Accept` header or the `?format=` query parameter. To simplify the API and eliminate schema duplication, `format_suffix_patterns` has been removed. Clients should now request specific formats via headers or query parameters instead of file extensions.

**include_docs_urls**

DRFs `include_docs_urls` to provide interactive API documentation. However, this utility depends on the deprecated CoreAPI and CoreJSON libraries, which have been removed from DRF and are now unmaintained. Continuing to use them generated deprecation warnings.

`include_docs_urls` was replaced with DRF’s built-in OpenAPI schema view