Case #545 - Prevent User From Uploading Original Text as Translation

[0xferit]

https://linguo.kleros.io/translation/0xa3E4348BDDc32AfcedC5e088e0E21FD6154A0180/2

The user mistakenly uploaded the original text file as the translation file. We can prevent this by comparing ipfs hashes of the original text and translated text and warn the user if matches.