Increase/remove the 10 MB limit on PDF files.

This should be a fix, 10 MB for PDF files does not work. A lot of PDF files are inflated with graphics/images making them more than 10 MB, without adding data the bot should be trained on.

Having to redo PDF files and remove graphics is a huge pain in the butt. So this limit should be increased to at least a couple of hundred MB to account for this.