Bug: Rounding error when using coin selection

[moneymanolis]

When using coin selection and send max (meaning using all the UTXOs selected) the amount selected is off. This seems to come from known issues in JavaScript when using floating point arithmetic (see here: https://ericlippert.com/2003/09/15/why-does-jscript-have-rounding-errors/). The relevant floating point arithemtic in this case is probably here:

specter-desktop/src/cryptoadvance/specter/templates/includes/coin_selection.html

Line 153 in c660e05

getCoinSelectedAmount() {

Screenshot of the issue: