qt/confirm_tx_dialog: fix qt warning
qt/confirm_tx_dialog: fix qt warning

QLayout::addChildLayout: layout "" already has a parent

pooler/electrum-ltc,vialectrum/vialectrum,spesmilo/electrum,wakiyamap/electrum-mona,pooler/electrum-ltc,vialectrum/vialectrum,pooler/electrum-ltc,spesmilo/electrum,wakiyamap/electrum-mona,vialectrum/vialectrum,spesmilo/electrum,spesmilo/electrum,wakiyamap/electrum-mona,wakiyamap/electrum-mona,pooler/electrum-ltc