Fix & clean up ExtUI (#14748)

Marlin/src/module/configuration_store.cpp

@@ -98,10 +98,8 @@
   #include "../feature/runout.h"
 #endif
 
-#include "../lcd/extensible_ui/ui_api.h"
-
 #if ENABLED(EXTRA_LIN_ADVANCE_K)
-extern float saved_extruder_advance_K[EXTRUDERS];
+  extern float saved_extruder_advance_K[EXTRUDERS];
 #endif
 
 #if EXTRUDERS > 1