DNS server stop independent of webserver type

In some situations (not passing a WebServer instance from external) the
DNS server was not stopped in _stopPortal(). Maybe the intention was here not
to stopped an externally passed WebServer but I see no use-case for the
dns server here.

Fixed this to remove the enum handling in the next step.

src/AutoConnect.cpp

@@ -385,13 +385,11 @@ void AutoConnect::end(void) {
   }
 
   _stopPortal();
+  _dnsServer.reset();
+
   if (_webServer) {
     switch (_webServerAlloc) {
     case AC_WEBSERVER_HOSTED:
-      if (_dnsServer) {
-        _dnsServer->stop();
-        _dnsServer.reset();
-      }
       _webServer.reset();
       break;
     case AC_WEBSERVER_PARASITIC:
@@ -686,7 +684,7 @@ bool AutoConnect::_loadAvailCredential(const char* ssid) {
  *  Stops DNS server and flush tcp sending.
  */
 void AutoConnect::_stopPortal(void) {
-  if (_dnsServer && _webServerAlloc == AC_WEBSERVER_HOSTED)
+  if (_dnsServer)
     _dnsServer->stop();
 
   if (_webServer) {