Slightly increased size of head for um2+

Discussed this with HW department, size of um2+ head is slightly bigger.

CURA-900

resources/machines/ultimaker2plus.json

@@ -15,6 +15,27 @@
         "machine_depth": { "default": 225 },
         "machine_height": { "default": 200 },
         "machine_show_variants": { "default": true },
-        "gantry_height": { "default": 50 }
+        "gantry_height": { "default": 50 },
+        "machine_head_with_fans_polygon":
+        {
+            "default": [
+                [
+                    -44,
+                    14
+                ],
+                [
+                    -44,
+                    -34
+                ],
+                [
+                    64,
+                    14
+                ],
+                [
+                    64,
+                    -34
+                ]
+            ]
+        }
     }
 }