Enable Alternate Wall Dirs for end-users too.

It's a little bit unclear, but the initial reason we set this to false was because we wanted to make sure most of the 'metal print' releated features dropped in 5.1, not 5.0?

still CURA-8097 .. sort of

resources/definitions/fdmprinter.def.json

@@ -8040,7 +8040,7 @@
                     "description": "Alternate wall directions every other layer and inset. Useful for materials that can build up stress, like for metal printing.",
                     "type": "bool",
                     "default_value": false,
-                    "enabled": false,
+                    "enabled": true,
                     "settable_per_mesh": true,
                     "settable_per_extruder": true
                 },