feat(dependencies): minimal default tag install (#3362)

tests/datasets/test_visualize_dataset.py

@@ -15,6 +15,8 @@
 # limitations under the License.
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.scripts.lerobot_dataset_viz import visualize_dataset