feat: Balance Check for Quote Verification

[nlordell]

Background

We currently require balances for quote verification. This adds additional overhead to clients that need to decide what kind of quote to make to the API. This is an issue for external integrations (for example DeFi Llama) where implementing quoting logic changes is more difficult and partially outside of our control.

Details

In the interim, however, we can change the trade simulation Solidity code to first check the trader has sufficient balance and:

• If it does, then simulate as we do now
• If it does not, return early and pretend the simulation passed and use the indicative amounts and gas usage for the quote

This would allow quotes to work from accounts without balance (for example, CoW Swap UI with a disconnected account) while still keeping the full benefit for

Note that there could be some abuse where a client could get a quote with an account without balance in order to "lock in" a fee using indicative (and not real) gas amounts, but I don't believe that this will be abused extensively in practice.

[MartinquaXD]

Implemented in #2330