bdk_electrum: use transaction-get verbose param

"In populate_with_txids you state "because of restrictions of the Electrum API, we have to use the script_get_history call to get confirmation status of our transaction". But Electrum supports a verbose parameter to the transaction.get call, which appears to return the number of confirmations of the transaction. See https://electrumx-spesmilo.readthedocs.io/en/latest/protocol-methods.html#blockchain-transaction-get"