2440/uni merge: gas amount always shows 37

[anxolin]

Related to #2536

1. Open the app
2. Connect to the Mainnet
3. Check the gas price at the bottom of the page

AR: always shows 37

ER: should show gas amount on sending TX on L1 from https://etherscan.io/gastracker

Original issue gnosis/cowswap#2640 by @elena-zh

[alfetopito]

Couple of points regarding the gas price:

1. Not very precise, as it takes hours to update and might not be relevant for current gas spikes
2. It's fetched from an onchain contract, and that's why I believe it's not updated very often
3. Is only available on mainnet. Doesn't make much sense on other networks anyway

So, we either change how it's updated or it's a won't fix

[W3stside]

this is also the case in uniswap, low prio