Command `goal wallet new $NAME` fails with `inappropriate ioctl` error

### Subject of the issue

When trying to create a new wallet through the sandbox, a prompt is displayed for the user to enter a password.

Because we dispatch the call with `dc exec -T ...`, no TTY is made available so an error occurs: `inappropriate ioctl for device`

Simply removing the `-T` flag from the `dc` subroutine allows it to work as expected but I'm sure causes issues elsewhere.

I think we'll need to figure out which goal commands require a TTY and when we see one, use the `dc_pty` subroutine

Docker 20.10.17