component AP gateway: set POST default response code to 202 (accepted)

sat/plugins/plugin_comp_ap_gateway/http_server.py

@@ -648,6 +648,8 @@ class HTTPAPGServer(web_resource.Resource):
             request.finish()
             return
 
+        # default response code, may be changed, e.g. in case of exception
+        self.responseCode(request, http.ACCEPTED)
         try:
             return await self.APRequest(request, signing_actor)
         except Exception as e: