Update Xenium dataset

[LucaMarconato]

The Xenium notebook is using a previous dataset (for XOA 2.0). We should consider using on the following recent datasets, recommended by the 10x team:

• FFPE Human Pancreas with Xenium Multimodal Cell Segmentation
• Fresh Frozen Mouse Colon with Xenium Multimodal Cell Segmentation

In alternative we could use the preview data for the 5K panel:

• Preview Data: FFPE Human Lymph Node with 5K Pan Tissue and Pathways Panel

Or even better,

• wait until a stable version of the 5K panel data is released and use that.