message: [web-service] catch exceptions in web server
diff: #include <server_http.hpp>
  #include "common/code_utils.hpp"
  +#include "common/logging.hpp"
  #define OT_ADD_PREFIX_PATH "^/add_prefix"
  #define OT_AVAILABLE_NETWORK_PATH "^/available_network$"
  @@ -132,12 +133,26 @@ void WebServer::StartWebServer(const char *aIfName, const char *aListenAddr, uin
  ResponseGetAvailableNetwork();
  ResponseCommission();
  DefaultHttpResponse();
  +
  + try
  + {
  mServer->start();
  + } catch (const std::exception &e)
  + {
  + otbrLog(OTBR_LOG_CRIT, "[web] failed to start web server: %s", e.what());
  + abort();
  + }
  }
  void WebServer::StopWebServer(void)
  +{
  + try
  {
  mServer->stop();
  + } catch (const std::exception &e)
  + {
  + otbrLog(OTBR_LOG_CRIT, "[web] failed to stop web server: %s", e.what());
  + }
  }
  void WebServer::HandleHttpRequest(const char *aUrl, const char *aMethod, HttpRequestCallback aCallback)
  