[MAINT]: Add provider configuration to set `auth_mode: 'anonymous'`

### Describe the need

We want to ensure that users can explicitly disable auth. Then `terraform` doesn't need to do extra work to check all other auth types.

### SDK Version

_No response_

### API Version

_No response_

### Relevant log output

```shell

```

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct