don't swallow responses on errors

[sakulstra]

I tried integrating with paraswap SDK, but felt like debugging is relatively hard.

When the api responds with an error code the complete response is swallowed making debugging kinda hellish.
I'd suggest do serve the response alongside the error instead of throwing it away as in the case of slippage errors like here: https://apiv2.paraswap.io/v2/prices/?from=0x7fc66500c84a76ad7e9c93437bfc5ac33e2ddae9&to=0x6b175474e89094c44da98b954eedeac495271d0f&amount=30000000000000000000000&side=BUY it might make sense to display some sort of feedback in the ui.