Removed User Story links from notebook

a_ddm_model_validation.ipynb

@@ -5,9 +5,7 @@
    "id": "irish-antibody",
    "metadata": {},
    "source": [
-    "# DDM: MODEL VALIDATION\n",
-    "User Story 21219: DDM - Model validation and improvement updates\n",
-    "> https://bizair.visualstudio.com/Machine%20Teaching%20CS/_workitems/edit/21219"
+    "# DDM: MODEL VALIDATION"
    ]
   },
   {
@@ -239,9 +237,7 @@
    "id": "imported-concentrate",
    "metadata": {},
    "source": [
-    "# 4. Pre-analysis: Estimated Error\n",
-    "Task 21357: DDM w Cartpole: Error propagation from initialization\n",
-    "> https://bizair.visualstudio.com/Machine%20Teaching%20CS/_workitems/edit/21357"
+    "# 4. Pre-analysis: Estimated Error"
    ]
   },
   {