fix header conversion in spin_sdk.http.send

Signed-off-by: Joel Dice <joel.dice@akamai.com>

Author: dicej

src/spin_sdk/http/__init__.py

@@ -190,6 +190,7 @@ async def send(request: Request) -> Response:
     incoming_response = await client.send(outgoing_request)
 
     status = incoming_response.get_status_code()
+    headers = incoming_response.get_headers().copy_all()
     rx, trailers = WasiResponse.consume_body(incoming_response, _unit_future())
     body = bytearray()
     with rx: