Since #13666 our fee calculation assumes that ECSDA signatures are a maximum of 71 bytes, rather than 72. However, not all hardware wallets implement R-value grinding.

This can cause us to underpay fees when using an external signer. That's especially problematic when the user picks 1 sat/vbyte as the fee, because it won't even get into our own mempool.

The easiest solution would be to modify `ExternalSignerScriptPubKeyMan` to assume 72 bytes for ECSDA signatures.

Slightly more advanced would be to expand HWI to keep track of which devices and firmware versions (if any) support R-value grinding. We'd then have to store that in the wallet in some new field. Personally I'd rather work on better Taproot support, which thanks to Schnorr avoids this issue altogether. 
assert( // This is a critical error, the new db could not be written to. The original db exists as a backup, but we should not continue execution.
        }
    }
    bool committed = batch->TxnCommit();
    assert(committed); // This is a critical error, the new db could not be written to. The original db exists as a backup, but we should not continue execution.
    return true;
}
stdoptional<MigrationData> CWalGetDescriptorsForLegacy(bilingual_str& error) const
{
    AssertLockHeld(cs_wal);
    LegacyScriptPubKeyMan* legacy_spkm = GetLegacyScriptPubKeyMan();
    assert(legacy_spkm);
    stdoptional<MigrationData> res = legacy_spkm->MigrateToDescriptor();
    if (res == stdnullopt) {
        error = _("Error Unable to produce s for this legacy wal. Make sure to provide th's passphrase if it is encrypted.");
        return stdnullopt;
    }
    return res;
}
bool CWalApplyMigrationData(MigrationData& data, bilingual_str& error)
{
    AssertLockHeld(cs_wal);
    LegacyScriptPubKeyMan* legacy_spkm = GetLegacyScriptPubKeyMan();
    if (!legacy_spkm) {
        error = _("Error This wal is already a  wal");
        return false;
    }
    for (auto& desc_spkm  data.desc_spkms) {
        if (m_spk_managers.count(desc_spkm->GetID()) > 0) {
            error = _("Error Duplicate s created during migration. Your wal may be corrupted.");