Invalid files for Datacomp1B

Hi,

The following urls from Datacomp1B will cause `img2dataset` to get stuck on the download and should be removed:
```
https://yimago.net/radio1/y1_images/dwight.jpg
https://yimago.net/radio1/y1_images/aj.jpg
https://yimago.net/radio1/y1_images/terri.jpg
```