[Enhancement]Make logger unchecked sendable

[ipavlidakis]

🔗 Issue Links

• Related to https://linear.app/stream/issue/IOS-1816
• Unblocks [Enhancement]Migrate sdk signaling core infra onto stream core swift stream-video-swift#1178

🎯 Goal

Allow Logger to be safely captured by @Sendable closures and restore the concurrency contract previously provided by StreamVideo’s logger.

📝 Summary

• Add @unchecked Sendable conformance to Logger.
• Add a Swift Testing concurrency regression test.
• Verify concurrent logging processes every message and preserves caller thread metadata.

🛠 Implementation

Logger now declares @unchecked Sendable because it is a reference type that supports concurrent logging through its serialized delivery queue.

The regression test uses a task group to log 200 messages concurrently and verifies that every message is processed.

☑️ Contributor Checklist

• I have signed the Stream CLA (required)
• This change should be manually QAed
• Changelog is updated with client-facing changes
• Changelog is updated with new localization keys
• New code is covered by unit tests
• Documentation has been updated in the docs-content repo

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[martinmitrevski]

lgtm