[bugfix] fix synth swap issues

Found a few bugs with synthetic asset swaps during manual testing.

The largest bug was in txout manager where, when sending synth out, the code treated it as it was a layer1 asset. It witheld some of the asset, and put it back into the pool increase the pool asset balance (when we have no additional asset to add tot he pool, causing an accounting issue, having more asset than the vault would have).