fix utxos update error
Currently, every time sendlotus retrieves utxos from api server, it is always different from the existing utxos stored in localstorage. This is caused by removing support for slp from original codebase. In emulating the returned hydratedUtxos (to avoid hitting the api server), we inadvertently modified the original utxos. This can be fixed by deep cloning the original utxos, and then emulating the hydatedUtxos by modifying the cloned-utxos