clickhousectl cloud auth status should show env vars

[sdairs]

When using env vars, cloud auth status gives no information about it.

clickhousectl cloud auth status
╭─────────┬────────────────┬───────╮
│ Type    │ Status         │ Scope │
├─────────┼────────────────┼───────┤
│ OAuth   │ Not configured │ -     │
│ API key │ Not configured │ -     │
╰─────────┴────────────────┴───────╯

we should include envars in this display and check for their existence.