Fix GNSS site name bug in final cell

Author: rzinke

methods/transient/Transient_Requirement_Validation.ipynb

@@ -1930,7 +1930,7 @@
     "        print(f\"Plotting GPS postion from {start_time_str} to {end_time_str} at station: {site_name}\")\n",
     "\n",
     "        # Retrieve GNSS time-series\n",
-    "        series = gnss_time_series[ifg_ndx, stn]\n",
+    "        series = gnss_time_series[ifg_ndx, site_name]\n",
     "\n",
     "        # Initialize figure\n",
     "        plt.figure(figsize=(15,5))\n",