chore: update openiap apple to 1.3.15 (#618)

## Summary

- Update openiap apple dependency to 1.3.15

## Changes

- watchOS 8+ platform support added
- visionOS 1.0 compatibility fixes

## OpenIAP Versions

| Package | Version |
|---------|---------|
| openiap-apple | 1.3.15 |
| openiap-google | 1.3.28 |
| openiap-gql | 1.3.17 |

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

## Summary by CodeRabbit

* **Chores**
  * Updated component version to 1.3.15

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

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: hyochan

openiap-versions.json

@@ -1,5 +1,5 @@
 {
-  "apple": "1.3.14",
+  "apple": "1.3.15",
   "google": "1.3.28",
   "gql": "1.3.17"
 }