Restore correct gMax 1.5+ G26 values

Marlin/example_configurations/gCreate/gMax1.5+/Configuration.h

@@ -913,10 +913,10 @@
   /**
    * Enable the G26 Mesh Validation Pattern tool.
    */
-  //#define G26_MESH_VALIDATION   // Enable G26 mesh validation
+  #define G26_MESH_VALIDATION   // Enable G26 mesh validation
   #if ENABLED(G26_MESH_VALIDATION)
-    #define MESH_TEST_NOZZLE_SIZE     0.4   // (mm) Diameter of primary nozzle.
-    #define MESH_TEST_LAYER_HEIGHT    0.2   // (mm) Default layer height for the G26 Mesh Validation Tool.
+    #define MESH_TEST_NOZZLE_SIZE     0.5   // (mm) Diameter of primary nozzle.
+    #define MESH_TEST_LAYER_HEIGHT    0.3   // (mm) Default layer height for the G26 Mesh Validation Tool.
     #define MESH_TEST_HOTEND_TEMP   205.0   // (°C) Default nozzle temperature for the G26 Mesh Validation Tool.
     #define MESH_TEST_BED_TEMP       60.0   // (°C) Default bed temperature for the G26 Mesh Validation Tool.
   #endif