A space in the column name breaks the assets URLs
reported internally by @xianbaoqian: https://huggingface.slack.com/archives/C02EMARJ65P/p1714493144145569

## with the space
![image](https://github.com/huggingface/dataset-viewer/assets/1676121/2c6f96eb-c42d-4a43-aa8f-00a66bbb9907)

![image](https://github.com/huggingface/dataset-viewer/assets/1676121/70ab3289-9a8e-4115-9f2c-c2c4d1f1d0b9)

## without the space

![image](https://github.com/huggingface/dataset-viewer/assets/1676121/6fb291b5-c73f-4639-89bc-ff1adbd8b9b1)

A space in the column name breaks the assets URLs: reported internally by @xianbaoqian: https://huggingface.slack.com/archives/C02EMARJ65P/p1714493144145569

## with the space
![image](https://github.com/huggingface/dataset-viewer/assets/1676121/2c6f96eb-c42d-4a43-aa8f-00a66bbb9907)

![image](https://github.com/huggingface/dataset-viewer/assets/1676121/70ab3289-9a8e-4115-9f2c-c2c4d1f1d0b9)

## without the space

![image](https://github.com/huggingface/dataset-viewer/assets/1676121/6fb291b5-c73f-4639-89bc-ff1adbd8b9b1)
