docs: Update elasticsearch.ipynb (#16090)

Fixed a typo, the parameter used for the Elasticsearch API key was
called api_key, but the parameter is called es_api_key.

docs/docs/integrations/vectorstores/elasticsearch.ipynb

@@ -75,7 +75,7 @@
     "        )\n",
     "```\n",
     "### Authentication\n",
-    "For production, we recommend you run with security enabled. To connect with login credentials, you can use the parameters `api_key` or `es_user` and `es_password`.\n",
+    "For production, we recommend you run with security enabled. To connect with login credentials, you can use the parameters `es_api_key` or `es_user` and `es_password`.\n",
     "\n",
     "Example:\n",
     "```python\n",