message: QT: Change bumpFee asserts to simple error message
diff: @@ -527,8 +527,10 @@ bool WalletModel::bumpFee(uint256 hash, uint256& new_hash)
  PartiallySignedTransaction psbtx(mtx);
  bool complete = false;
  const TransactionError err = wallet().fillPSBT(psbtx, complete, SIGHASH_ALL, false /* sign */, true /* bip32derivs */);
  - assert(!complete);
  - assert(err == TransactionError::OK);
  + if (err != TransactionError::OK || complete) {
  + QMessageBox::critical(nullptr, tr("Fee bump error"), tr("Can't draft transaction."));
  + return false;
  + }
  // Serialize the PSBT
  CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
  ssTx << psbtx;
  