Fix operation of length 1 strips, such as PWM LEDs

This reverts commit e5ba97bbe2.

wled00/FX_fcn.cpp

@@ -1340,11 +1340,6 @@ void WS2812FX::blendSegment(const Segment &topSegment) const {
   uint8_t       opacity    = topSegment.currentBri(); // returns transitioned opacity for style FADE
   uint8_t       cct        = topSegment.currentCCT();
 
-  if (length == 1) {
-    // Can't blend only a single pixel, prevents crash when bus init fails
-    return;
-  }
-
   Segment::setClippingRect(0, 0);             // disable clipping by default
 
   const unsigned dw = (blendingStyle==BLEND_STYLE_OUTSIDE_IN ? progInv : progress) * width / 0xFFFFU + 1;