coldcard tx dialog: "export PSBT" button should not raise on foreign ks
coldcard tx dialog: "export PSBT" button should not raise on foreign ks

tested trezor/coldcard mixed multisig and it worked; no reason to enforce
that the first keystore must be coldcard (order should not matter)

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