Make M7219 I more robust and nice to look at

Make M2719 initialize the Max7219 registers and then run the initialization pattern (if one is specified).

Marlin/src/gcode/feature/leds/M7219.cpp

@@ -42,8 +42,10 @@
  *               rows or columns depending upon rotation)
  */
 void GcodeSuite::M7219() {
-  if (parser.seen('I'))
+  if (parser.seen('I')) {
     Max7219_Clear();
+    Max7219_init();
+  }
 
   if (parser.seen('F'))
     for (uint8_t x = 0; x < MAX7219_X_LEDS; x++)