A user reported to me that they are unable to create a PSBT with a legacy watchonly wallet when they use the GUI. They get an error "The amount exceeds your balance".

I think the issue is that the GUI will retrieve the wallet's balance via `AvailableCoins` before calling `CreateTransaction`. This call to `AvailableCoins` is resulting in fewer coins being returned with recent changes to how `AvailableCoins` works, particularly with additional filtering of spendable coins and preset coins.

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Note that this does not effect descriptor wallets. A workaround for this issue is to switch to using descriptor wallets. An existing legacy wallet can be turned into a descriptor wallet using the `migratewallet` RPC. However many watchonly legacy wallets are likely the result of importing descriptors via `importmulti`. For such wallets, I recommend creating a new descriptor wallet and re-importing the descriptors.
{
    switch (type) {
        case TxoutType::WITNESS_V1_TAPROOT:
            return OutputType::BECH32M;
        case TxoutType::WITNESS_V0_KEYHASH:
        case TxoutType::WITNESS_V0_SCRIPTHASH:
            if (is_from_p2sh) return OutputType::P2SH_SEGWIT;
            else return OutputType::BECH32;
        case TxoutType::SCRIPTHASH:
        case TxoutType::PUBKEYHASH:
            return OutputType::LEGACY;
        default:
            return OutputType::UNKNOWN;
    }
}
util::Result<PreSelectedInputs> FetchSelectedInputs(const CWallet& wallet, const CCoinControl& coin_control,
                                            const CoinSelectionParams& coin_selection_params) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
    PreSelectedInputs result;
    std::vector<COutPoint> vPresetInputs;
    coin_control.ListSelected(vPresetInputs);
    const bool can_grind_r = wallet.CanGrindR();
    for (const COutPoint& outpoint : vPresetInputs) {
        int input_bytes = -1;
        CTxOut txout;