v4.0.6

## Warning
Do not upgrade to this release if you want to preserve your existing indexed documents but have not yet run the document index migration, which can be done from any version v3.x. [See additional documentation here](https://docs.onyx.app/admins/advanced_configs/opensearch_document_index_migration#opensearch-document-index-migration).

See the assets to download this version and install.

## What's Changed
* fix(connectors): add optional AWS region to S3 connector for non-default partitions (#11676) to release v4.0 by @onyx-cherry-pick[bot] in https://github.com/onyx-dot-app/onyx/pull/11682
* feat(craft): remove skills page from main admin panel (v4.0 cherry-pick) by @rohoswagger in https://github.com/onyx-dot-app/onyx/pull/11747
* fix: accept empty choices packet from LLM (#11752) to release v4.0 by @onyx-cherry-pick[bot] in https://github.com/onyx-dot-app/onyx/pull/11759
* fix(craft): tolerate unknown SANDBOX_BACKEND values instead of crashing (#11746) to release v4.0 by @rohoswagger in https://github.com/onyx-dot-app/onyx/pull/11750
* fix(slack): skip doc-set and persona access checks for anonymous Slack bot users (#11817) to release v4.0 by @justin-tahara in https://github.com/onyx-dot-app/onyx/pull/11821

**Full Changelog**: https://github.com/onyx-dot-app/onyx/compare/v4.0.5...v4.0.6