[fix] engine: brave - BrotliDecoderDecompressStream encoding issue (#5572)

For some reason, I keep getting this error from the brave engine:

    httpx.DecodingError: BrotliDecoderDecompressStream failed while processing the stream

Forcing the server to use either gzip or deflate fixes this issue.

This makes the brave engine work when the server seems to be encoding brotli incorrectly, or at least in a way incompatible with certain installs.

Related:

- https://github.com/searxng/searxng/pull/1787
- https://github.com/searxng/searxng/pull/5536

searx/engines/brave.py

@@ -214,6 +214,7 @@ def request(query: str, params: dict[str, t.Any]) -> None:
     if brave_category == "goggles":
         args["goggles_id"] = Goggles
 
+    params["headers"]["Accept-Encoding"] = "gzip, deflate"
     params["url"] = f"{base_url}{brave_category}?{urlencode(args)}"
     logger.debug("url %s", params["url"])