fix : replace deprecated datetime.utcnow with timezone-aware alternative in ui_enhancement

[tmdeveloper007]

Summary of What Needs to be Done

Replace usage of the deprecated datetime.utcnow() in src/utils/ui_enhancement.py with the timezone-aware datetime.now(timezone.utc).

Changes that Need to be Made

In src/utils/ui_enhancement.py:

1. Add timezone to the import: from datetime import datetime, timezone
2. Replace str(datetime.utcnow()) with datetime.now(timezone.utc).isoformat() in track_navigation_flow method

Impact that it Would Provide

• Fixes Python 3.12+ deprecation warning for datetime.utcnow()
• Uses the recommended timezone-aware datetime approach
• Better timezone correctness for navigation tracking timestamps

Note: Please assign this issue to the tmdeveloper007 account.