fix: px.Client().get_dataset_versions should use self._client.get…

… instead of `httpx.get` (#5220)

src/phoenix/session/client.py

@@ -414,7 +414,7 @@ def get_dataset_versions(
             pandas DataFrame
         """
         url = urljoin(self._base_url, f"v1/datasets/{dataset_id}/versions")
-        response = httpx.get(url=url, params={"limit": limit})
+        response = self._client.get(url=url, params={"limit": limit})
         response.raise_for_status()
         if not (records := response.json()["data"]):
             return pd.DataFrame()