Seed phrase account restoration not working

Hey!

When I try to deploy a DAO using the starter-template project and specifying a seed phrase in `.env` it is not able to get the account information. It seems it is not implemented in `migrations/deployDao.js` and tries to use the private key anyways.

Greetings
Freddy

Error message:
```✖ Could not obtain an account for migration. Please specify a valid 'private-key' or 'mnemonic'
TypeError: Cannot read property 'slice' of undefined
at Object.fromPrivate
```

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