Fix Bootmgic Mod Handling for LM keycodes (#4740)

quantum/keymap_common.c

@@ -127,7 +127,7 @@ action_t action_for_key(uint8_t layer, keypos_t key)
             action.code = ACTION_LAYER_TAP_TOGGLE(keycode & 0xFF);
             break;
         case QK_LAYER_MOD ... QK_LAYER_MOD_MAX:
-            mod = keycode & 0xF;
+            mod = mod_config(keycode & 0xF);
             action_layer = (keycode >> 4) & 0xF;
             action.code = ACTION_LAYER_MODS(action_layer, mod);
             break;