Fix probe_offset EEPROM field test

Marlin/src/module/configuration_store.cpp

@@ -614,10 +614,10 @@ void MarlinSettings::postprocess() {
     }
 
     //
-    // Probe Z Offset
+    // Probe XYZ Offsets
     //
     {
-      _FIELD_TEST(probe_offset.z);
+      _FIELD_TEST(probe_offset);
       EEPROM_WRITE(probe_offset);
     }