After https://github.com/bitcoin/bitcoin/pull/27037 miniscript is extracted from compatible scripts, unless the `FillableSigningProvider::AddCScript` check for `MAX_SCRIPT_ELEMENT_SIZE` fails, which then it falls back to legacy behavior.

@achow101 
{
    return RPCHelpMan{"joinpsbts",
            "\nJoins multiple distinct PSBTs with different inputs and outputs into one PSBT with inputs and outputs from all of the PSBTs\n"
            "No input in any of the PSBTs can be in more than one of the PSBTs.\n",
            {
                {"txs", RPCArg::Type::ARR, RPCArg::Optional::NO, "The base64 strings of partially signed transactions",
                    {
                        {"psbt", RPCArg::Type::STR, RPCArg::Optional::NO, "A base64 string of a PSBT"}
                    }}
            },
            RPCResult {
                    RPCResult::Type::STR, "", "The base64-encoded partially signed transaction"
            },
            RPCExamples {