Adding page number in image tags

### 🚀 The feature, motivation and pitch

It would be helpfull to change the image tag as foolow :
from :
(page_startx_starty_width_height.png)
To :
(page_number_startx_starty_width_height.png)

File : [olmocr](https://github.com/allenai/olmocr/tree/1987422508fb35ee62c184ca681ec63bd734a58a)/[olmocr](https://github.com/allenai/olmocr/tree/1987422508fb35ee62c184ca681ec63bd734a58a/olmocr)/[prompts](https://github.com/allenai/olmocr/tree/1987422508fb35ee62c184ca681ec63bd734a58a/olmocr/prompts)
/prompts.py
this will help in the future to auto extract figures and graphs.
@jakep-allenai

### Alternatives

_No response_

### Additional context

_No response_