fix(session): close null user

[alperozturk96]

📝 Summary

Pressing back from Android Files client calls close function however user was null this was causing 423 LOCKED on text file thus Notes app fail to sync. As fallback we can get user via documentId, sessionId, sessionToken

Android Files PR: nextcloud/android#17822

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI tools
• The AI-generated content was reviewed, comprehended and tested by a human