Change backend to least_busy

Author: kaelynj

docs/guides/build-noise-models.ipynb

@@ -103,15 +103,15 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": null,
    "id": "3c114909-aa2a-4638-b945-e31dcdbaf248",
    "metadata": {},
    "outputs": [],
    "source": [
     "from qiskit_ibm_runtime import QiskitRuntimeService\n",
     "\n",
     "service = QiskitRuntimeService()\n",
-    "backend = service.backend(\"ibm_brisbane\")\n",
+    "backend = service.least_busy()\n",
     "noise_model = NoiseModel.from_backend(backend)"
    ]
   },

docs/guides/dynamical-decoupling-pass-manager.ipynb

@@ -46,15 +46,15 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "id": "368cab01-8eb0-4feb-a5d1-269d225af7af",
    "metadata": {},
    "outputs": [],
    "source": [
     "from qiskit_ibm_runtime import QiskitRuntimeService\n",
     "\n",
     "service = QiskitRuntimeService()\n",
-    "backend = service.backend(\"ibm_brisbane\")\n",
+    "backend = service.least_busy()\n",
     "\n",
     "target = backend.target\n",
     "basis_gates = list(target.operation_names)"