[Docs]: clarify where a community Sealos deployment option belongs

### Page URL

https://docs.airbyte.com/platform/deploying-airbyte/deploying-airbyte

### Description

A community-maintained Sealos template provides a tested one-click path for users who run Airbyte on Sealos. I would like maintainer guidance on the preferred location for a short community deployment link before preparing a documentation PR.

Proposed target: https://sealos.io/products/app-store/airbyte

The smallest change would add a brief community deployment callout to `docs/platform/deploying-airbyte/deploying-airbyte.md`, while preserving the official Helm guidance as the primary Kubernetes installation path.

Validation evidence:

- Airbyte images: `2.1.0`
- Tested deployment: 2026-08-05
- The template provisions Airbyte services, PostgreSQL, Temporal, persistent storage, ingress, and generated credentials.
- Browser smoke covered setup and representative navigation.
- Runtime log scans ended with zero active failures, and all verification resources were cleaned up.
- The template and documentation are maintained outside the Airbyte repository; I can own follow-up updates for this deployment path.

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**Internal Tracking:** https://github.com/airbytehq/oncall/issues/13240