Improve our "max" logic, or allow max via legacy tx, or at least improve our copy related to "max"

Nobody has claimed this yet.

We had this feedback on twitter:

> The new metamask always leaves my wallet with like $0.73 dollars of ETH in it after I do a "max" transfer. This is fucking infurating I have like 7 wallets with dust in them now

And there was this reply:

> Only way to empty a wallet post-1559 is to send a legacy txn, or to set your max priority fee to your max fee (they are equivalent). It is one of the downsides of it. FWIW, "emptying" in this case will just send more to the miner vs. to your other wallet, so for you it's equal.

We should do the following:

1. investigate to ensure that our "Max" button/mode is doing the best it can, and that there was no degradation with EIP-1559 beyond what is unavoidable given the protocol level changes
2. consider whether we want to allow the user to "empty" their wallet via a legacy tx (probably not right?)
3. If we don't change anything in response to steps 1 and 2, we might want to consider whether any copy or information changes could help users wanting to "empty" their account.

Start with the Max transfer flow and the transaction construction logic, then compare its behavior under EIP-1559 with legacy transactions. Determine whether any remaining balance is avoidable, whether legacy emptying should be supported, and whether user-facing copy needs updating; done means a documented decision and corresponding implementation or copy change.

Written by the indexing model from the issue text.