Update Obtain credentials using TokenLibrary.ipynb

Author: nirav2

Notebooks/Scala/Obtain credentials using TokenLibrary.ipynb

@@ -44,6 +44,7 @@
         "// Example connection string (for storage): \"DefaultEndpointsProtocol=https;AccountName=<accountname>;AccountKey=<accountkey>\"\n",
         "\n",
         "val connectionString: String = TokenLibrary.getConnectionString(\"<linkedServiceName>\")\n",
+        "val accountKey: String = TokenLibrary.getConnectionStringAsMap(\"<linkedServiceName>\").get("AccountKey")\n",
         ""
       ],
       "attachments": {}