Note footers should not be 0 in curveRemoveLiquidity() if the corresponding assetOuts are non null
Description
In curveRemoveLiquidity(), the note footer should not be allowed to be 0 if assetOut is non null, as this could lead to duplicate note footers.
Recommendation
Revert if the note footer is 0 but the corresponding asset out is not.
Status
Addressed in #8b300f0.