fix(python): Recover deployment log pages

[tchaton]

Why

Deployment replicas can store complete logs without legacy page metadata, causing DeploymentApi.get_job_logs() to return an empty response even when logs exist.

What changed

When a deployment job has no legacy pages, the SDK now exposes the complete log download as a compatible single page. Existing pages, time-filtered requests, and unavailable downloads retain their previous behavior.

Testing

• uv run --project python pytest python/tests/api/test_deployment_api.py -q (6 passed)
• Ruff lint and format checks on both changed files

_{— GPT-5 Codex, via /create-pr; text not reviewed}