Dear Maintainer,

Running `dumppdf -at` on the following PDF file:
https://github.com/user-attachments/files/29155207/allabout.pdf

emits this error:
```
  File "/usr/lib/python3/dist-packages/pdfminer/utils.py", line 215, in apply_png_predictor
    prior_x = int(line_above[j])
                  ~~~~~~~~~~^^^
IndexError: list index out of range
```

See full error here: https://github.com/pdfminer/pdfminer.six/issues/1269
There is a patch to fix this here: https://github.com/pdfminer/pdfminer.six/pull/1270

This is related to bug #1140397 for diffoscope.

There is a related patch here which resolves the issue at a different
level:
https://github.com/pdfminer/pdfminer.six/pull/1271

I think it would be good to apply both patches, for safety. We'll see
what upstream decides.