Add POKE_ICON_BASE_PAL_TAG to a header

src/pokemon_storage_system.c

@@ -40,6 +40,7 @@
 #include "constants/moves.h"
 #include "constants/rgb.h"
 #include "constants/songs.h"
+#include "constants/pokemon_icon.h"
 
 /*
     NOTE: This file is large. Some general groups of functions have
@@ -215,7 +216,7 @@ enum {
 #define BOXID_CANCELED    201
 
 enum {
-    PALTAG_MON_ICON_0 = 56000,
+    PALTAG_MON_ICON_0 = POKE_ICON_BASE_PAL_TAG,
     PALTAG_MON_ICON_1, // Used implicitly in CreateMonIconSprite
     PALTAG_MON_ICON_2, // Used implicitly in CreateMonIconSprite
     PALTAG_3, // Unused