some effect optimizations

* getpixelcolor: attribute pure - it reads memory, but does not write
* some optimizations for SEGMENT.blur() and SEGMENT.fadeToBlackBy()

* FX.c:pp remove double calls to blur() and fade_out()
* FX.cpp: SEGMENT.setUpLeds() added to effects, to enable LED buffering (safe some time because getPixelColor does not need to access NeopixelBus)

* a few other optimizations to safe time and avoid "expensive" operations
* set I2C bus speed to 400kHz (default is 100Khz)

* a few other small optimizations and tweaks
* pio: esp32 V4 builds use "patch5" toolchain version, which contains a few bugfixes especially for memory management.

wled00/ws.cpp

@@ -185,8 +185,8 @@ static bool sendLiveLedsWs(uint32_t wsClient)  // WLEDMM added "static"
 #ifndef WLED_DISABLE_2D
   if (strip.isMatrix) {
     buffer[1] = 2; //version
-    buffer[2] = Segment::maxWidth;
-    buffer[3] = Segment::maxHeight;
+    buffer[2] = min(Segment::maxWidth, (uint16_t) 255); // WLEDMM prevent overflow
+    buffer[3] = min(Segment::maxHeight, (uint16_t) 255);
     //WLEDMM: no skipLines
   }
 #endif