feat: enable CodeRabbit reviews on draft PRs (#8587)

Enable CodeRabbit to automatically review draft pull requests.

## Changes
- Added `reviews.auto_review.drafts: true` to `.coderabbit.yaml`

This allows getting early feedback from CodeRabbit while PRs are still
in draft status.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
  * Enabled automatic review drafting to streamline the review process.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8587-feat-enable-CodeRabbit-reviews-on-draft-PRs-2fc6d73d365081ea8f1bcae4a2a8277b)
by [Unito](https://www.unito.io)

.coderabbit.yaml

@@ -1,3 +1,6 @@
 issue_enrichment:
   auto_enrich:
     enabled: true
+reviews:
+  auto_review:
+    drafts: true