free udp receive buffers before parsePacket

robustness improvement - parsepacket() will fail if the udp handler still has an active receive buffer.

wled00/ntp.cpp

@@ -226,6 +226,7 @@ void sendNTPPacket()
 
 bool checkNTPResponse()
 {
+  ntpUdp.flush();
   int cb = ntpUdp.parsePacket();
   if (!cb) return false;
 

wled00/udp.cpp

@@ -240,8 +240,10 @@ void handleNotifications()
   if (!udpConnected) return;
 
   bool isSupp = false;
+  notifierUdp.flush();
   int packetSize = notifierUdp.parsePacket();    // WLEDMM function returns int, not size_t
   if ((packetSize < 1) && udp2Connected) {
+    notifier2Udp.flush();
     packetSize = notifier2Udp.parsePacket();
     isSupp = true;
   }
@@ -249,6 +251,7 @@ void handleNotifications()
 
   //hyperion / raw RGB
   if (!packetSize && udpRgbConnected) {
+    rgbUdp.flush();
     packetSize = rgbUdp.parsePacket();
     if (packetSize) {
       if (!receiveDirect) {rgbUdp.flush(); notifierUdp.flush(); notifier2Udp.flush(); return;}