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.
{
        std::vector<std::unique_ptr<Wallet>> wallets;
        for (const auto& wallet : GetWallets(m_context)) {
            wallets.emplace_back(MakeWallet(m_context, wallet));
        }
        return wallets;
    }
    std::unique_ptr<Handler> handleLoadWallet(LoadWalletFn fn) override
    {
        return HandleLoadWallet(m_context, std::move(fn));
    }
    WalletContext* context() override  { return &m_context; }
    WalletContext m_context;
    const std::vector<std::string> m_wallet_filenames;
    std::vector<std::unique_ptr<Handler>> m_rpc_handlers;
    std::list<CRPCCommand> m_rpc_commands;
};
} 
} 
namespace interfaces {
std::unique_ptr<Wallet> MakeWallet(wallet::WalletContext& context, const std::shared_ptr<wallet::CWallet>& wallet) { return wallet ? std::make_unique<wallet::WalletImpl>(context, wallet) : nullptr; }
std::unique_ptr<WalletLoader> MakeWalletLoader(Chain& chain, ArgsManager& args)
{
    return std::make_unique<wallet::WalletLoaderImpl>(chain, args);
}
}