update tests for new start&end fields

Author: Dieterbe

test/fixtures/nutrition/nutritional_plan_detail_response.json

@@ -2,6 +2,8 @@
   "id": 1,
   "creation_date": "2022-08-09",
   "description": "",
+  "start": "2022-08-01",
+  "end": null,
   "only_logging": false,
   "goal_energy": null,
   "goal_protein": null,

test/fixtures/nutrition/nutritional_plan_info_detail_response.json

@@ -2,6 +2,8 @@
     "id": 92547,
     "creation_date": "2024-04-01",
     "description": "first real cut",
+    "start": "2024-04-01",
+    "end": null,
     "only_logging": false,
     "goal_energy": 1600,
     "goal_protein": 150,