Fix output glitches when playlist changes preset (#4442)

same issue as with #4386
waiting on bus to finish updating before file access fixes the glitches.
this issue is only present on S2 and C3, not on ESP8266 or dual-core ESPs, the fix is only applied for these two.

Author: DedeHai

wled00/presets.cpp

@@ -164,6 +164,11 @@ void handlePresets()
 
   DEBUG_PRINTF_P(PSTR("Applying preset: %u\n"), (unsigned)tmpPreset);
 
+  #if defined(ARDUINO_ARCH_ESP32S2) || defined(ARDUINO_ARCH_ESP32C3)
+  unsigned long start = millis();
+  while (strip.isUpdating() && millis() - start < FRAMETIME_FIXED) yield(); // wait for strip to finish updating, accessing FS during sendout causes glitches
+  #endif
+
   #ifdef ARDUINO_ARCH_ESP32
   if (tmpPreset==255 && tmpRAMbuffer!=nullptr) {
     deserializeJson(*pDoc,tmpRAMbuffer);