UX to show "unlimited" on Approve screen per EIP717

[p-s-dev]

What problem are you trying to solve?
User are confused when seeing "you grant permission for this contract to spend up to 1.158e+59 of your DAI"

Describe the solution you'd like
User would more easily understand "you grant permission for this contract to spend an unlimited amount of your DAI"

Additional context
if (approveAmount == uint(-1)) : UxMessage = "an unlimited amount"

[bdresser]

@p-s-dev agree, the confirm screen for Approves can be pretty daunting, we'll be taking a look shortly.

[RikaGoldberg]

Very excited for this change to be made. Will clear up a lot of confusion for users. Thanks.

[Gudahtt]

This was implemented in #7271