Fix UBL Mesh Size regression

Marlin/src/inc/Conditionals_post.h

@@ -1064,10 +1064,13 @@
     #define _MESH_MAX_Y (MAX_PROBE_Y - (MESH_INSET))
   #else
     // Boundaries for Cartesian probing based on set limits
-    #define _MESH_MIN_X (max(X_MIN_BED + MESH_INSET, X_MIN_POS + X_PROBE_OFFSET_FROM_EXTRUDER))
-    #define _MESH_MIN_Y (max(Y_MIN_BED + MESH_INSET, Y_MIN_POS + Y_PROBE_OFFSET_FROM_EXTRUDER))
-    #define _MESH_MAX_X (min(X_MAX_BED - (MESH_INSET), X_MAX_POS + X_PROBE_OFFSET_FROM_EXTRUDER))
-    #define _MESH_MAX_Y (min(Y_MAX_BED - (MESH_INSET), Y_MAX_POS + Y_PROBE_OFFSET_FROM_EXTRUDER))
+    #if ENABLED(AUTO_BED_LEVELING_UBL)
+      #define _MESH_MIN_X (max(X_MIN_BED + MESH_INSET, X_MIN_POS))  // UBL is careful not to probe off the bed.  It does not
+      #define _MESH_MIN_Y (max(Y_MIN_BED + MESH_INSET, Y_MIN_POS))  // need *_PROBE_OFFSET_FROM_EXTRUDER in the mesh dimensions
+    #else
+      #define _MESH_MIN_X (max(X_MIN_BED + MESH_INSET, X_MIN_POS + X_PROBE_OFFSET_FROM_EXTRUDER))
+      #define _MESH_MIN_Y (max(Y_MIN_BED + MESH_INSET, Y_MIN_POS + Y_PROBE_OFFSET_FROM_EXTRUDER))
+    #endif
   #endif
   /**
    * These may be overridden in Configuration if a smaller area is wanted