Make default layer size 16-bit (#15286)

Co-authored-by: James Young <18669334+noroadsleft@users.noreply.github.com>

keyboards/ergoslab/keymaps/default/keymap.c

@@ -51,7 +51,7 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
 
 #ifdef RGBLIGHT_ENABLE
 layer_state_t layer_state_set_user(layer_state_t state) {
-  uint8_t layer = biton32(state);
+  uint8_t layer = get_highest_layer(state);
   switch (layer) {
       case BASE:
           rgblight_sethsv(HSV_ERGOSLAB_ORANGE);