Add dollar amounts when clicking "Add" for "Gas on destination"

[awbvious]

It's nice that there's slippage tolerance on bridging, but there's zero consideration for slippage when it comes to gas. if you do max gas when bridging from Optimism to Metis, the amount of ETH you spend (approx 0.0928 or $334 per last check) gets you much less METIS than you would expect (2.5 METIS or $254 per last check). That's 24% slippage. However, the UI only shows you the amount of ETH you are spending and the amount of METIS you are getting, so it is hard to know how bad the slippage is. Further, it is quite possible that someone bridging 2.5 METIS would not realize that is far more gas than they will need. I am attaching images of both the current UI and a proposed UI to show the difference.