🩹 Fix missing HAS_DUAL_Y_STEPPERS (#27024)

Co-authored-by: ellensp <[email protected]>

Author: thisiskeithb

Marlin/src/inc/Conditionals_LCD.h

@@ -456,6 +456,7 @@
 #endif
 #ifdef Y2_DRIVER_TYPE
   #define HAS_Y2_STEPPER 1
+  #define HAS_DUAL_Y_STEPPERS 1
 #endif
 
 /**