--mnemonic flag is required in existing-mnemonic subcommand

[ank-everstake]

When you want to generate keys from existing-mnemonic - command fails if you do not provide --mnemonic flag:

./eth-staking-smith existing-mnemonic --withdrawal_credentials 0x0000000000000000000000000000000000000000 --num_validators 1 --chain mainnet
error: The following required arguments were not provided:
    --mnemonic <mnemonic>

USAGE:
    eth-staking-smith existing-mnemonic --chain <chain> --mnemonic <mnemonic> --num_validators <num_validators> --withdrawal_credentials <withdrawal_credentials>

However help states that you can omit this flag and you will be prompted on console:

        --mnemonic <mnemonic>
            The mnemonic that you used to generate your
                            keys. (It is recommended not to use this
                            argument, and wait for the CLI to ask you
                            for your mnemonic as otherwise it will
                            appear in your shell history.)

[mksh]

Thanks for the report, this will be easy to implement, will do -- mnemonic will be either read from stdin, or asked as an input

[ank-everstake]

@mksh Any updates on the issue?