accept up to 250 fps target in LED preferences

warning included.

wled00/wled.cpp

@@ -211,6 +211,8 @@ void WLED::loop()
   //LED settings have been saved, re-init busses
   //This code block causes severe FPS drop on ESP32 with the original "if (busConfigs[0] != nullptr)" conditional. Investigate!
   if (doInitBusses) {
+    unsigned long waitStart = millis();                                             // WLEDMM: to avoid crash,
+    while (strip.isUpdating() && (millis() - waitStart < 250)) {yield(); delay(5);} // wait a bit until busses are idle (max 250ms)
     doInitBusses = false;
     DEBUG_PRINTLN(F("Re-init busses."));
     bool aligned = strip.checkSegmentAlignment(); //see if old segments match old bus(ses)