Rewrite remember_the_milk tests to pytest style tests (#41002)

* ✅ rewrite remember_the_milk tests to pytest tests

* ✅ rewrite reddit tests to pytest tests

* Revert "✅ rewrite reddit tests to pytest tests"

This reverts commit 7eae35f69a.
Forgot to switch to a new branch 🙈

tests/components/remember_the_milk/const.py

@@ -0,0 +1,14 @@
+"""Constants for remember_the_milk tests."""
+
+import json
+
+PROFILE = "myprofile"
+TOKEN = "mytoken"
+JSON_STRING = json.dumps(
+    {
+        "myprofile": {
+            "token": "mytoken",
+            "id_map": {"1234": {"list_id": "0", "timeseries_id": "1", "task_id": "2"}},
+        }
+    }
+)