Teporary fix to release PDU session

src/amf-app/amf_n1.cpp

@@ -3438,7 +3438,11 @@ void amf_n1::ue_initiate_de_registration_handle(
           assert(!smf_responses.begin()->second.has_exception());
           // Wait for the result from APP and send reply to AMF
           uint32_t http_response_code = smf_responses.begin()->second.get();
-          // TODO: process response code
+
+          // Remove PDU session
+          if ((http_response_code == 200) or (http_response_code == 204)) {
+            uc->remove_pdu_sessions_context(session->pdu_session_id);
+          }
         }
         smf_responses.erase(smf_responses.begin());
       }