Use `azd init` instead of `gh repo clone`

[v-jiaodi]

For azd templates, it is recommended to use azd init to initialize the project. At the same time, there is no need to pre install github CLI.

Suggestion:
Update gh repo clone graemefoster/LockedDownChatBot and cd LockedDownChatBot to azd init -t graemefoster/LockedDownChatBot.

@hemarina for notification.

[graemefoster]

Done