Reset all first start actions for UM2go

CURA-3742

resources/definitions/ultimaker2_go.def.json

@@ -13,7 +13,7 @@
         "platform": "ultimaker2go_platform.obj",
         "platform_texture": "Ultimaker2Gobackplate.png",
         "platform_offset": [0, 0, 0],
-        "first_start_actions": [""],
+        "first_start_actions": [],
         "supported_actions":["UpgradeFirmware"]
     },