docs: point to titantic dataset on web (#19455)

Updated `pd.read_csv("titantic.csv")` to
`pd.read_csv("https://raw.githubusercontent.com/pandas-dev/pandas/main/doc/data/titanic.csv")`
i.e. it will read it
https://raw.githubusercontent.com/pandas-dev/pandas/main/doc/data/titanic.csv
and allow anyone to run the code.

Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>

docs/docs/integrations/toolkits/pandas.ipynb

@@ -34,7 +34,9 @@
     "import pandas as pd\n",
     "from langchain_openai import OpenAI\n",
     "\n",
-    "df = pd.read_csv(\"titanic.csv\")"
+    "df = pd.read_csv(\n",
+    "    \"https://raw.githubusercontent.com/pandas-dev/pandas/main/doc/data/titanic.csv\"\n",
+    ")"
    ]
   },
   {