[BUG] admin account has to be imported and not generated

**Description:**
admin account is generated so it can't mint the fungible token.

**Steps to reproduce:**
1. search for admin in https://docs.cedra.network/guides/first-fa#4-typescript-client--testing-flow

**Expected behavior:**
admin account should be imported from the private key used to deploy the fungible token.

**Actual behavior:**
admin account is generated so it can't mint the fungible token.

**Possible fix:**
Use the source code in fa-example which works already.