🚸 MKS UI extrusion speed/steps config (#22656)

Marlin/src/lcd/extui/mks_ui/draw_ui.h

@@ -208,7 +208,7 @@ typedef struct {
   uint32_t  curFilesize;
 } CFG_ITMES;
 
-typedef struct {
+typedef struct UI_Config_Struct {
   uint8_t curTempType:1,
           extruderIndex:3,
           stepHeat:4,
@@ -228,8 +228,16 @@ typedef struct {
   uint8_t wifi_name[32];
   uint8_t wifi_key[64];
   uint8_t cloud_hostUrl[96];
+  // Extruder Steps distances (mm)
   uint8_t extruStep;
+  static constexpr uint8_t eStepMin =  1,
+                           eStepMed =  5,
+                           eStepMax = 10;
+  // Extruder speed (mm/s)
   uint8_t extruSpeed;
+  static constexpr uint8_t eSpeedH =  1,
+                           eSpeedN = 10,
+                           eSpeedL = 20;
   uint8_t print_state;
   uint8_t stepPrintSpeed;
   uint8_t waitEndMoves;