fix qt invoices list: handle lightning disabled
fix qt invoices list: handle lightning disabled

closes #5738

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