🧹 Code Health Improvement: Replace print with log in NetworkService

[LeanBitLab]

🎯 What: The code health issue addressed was replacing standard print statements with log from dart:developer in lib/providers/network_service.dart.
💡 Why: This improves maintainability and robustness by using standard robust logging instead of simple print calls, which can cause unneeded output noise and aren't easy to filter.
✅ Verification: Ran flutter test test/providers/network_service_test.dart and flutter test test/network_service_debug_test.dart to verify that no core functionalities were negatively impacted by the refactoring change.
✨ Result: The improvement successfully addressed code health metrics related to print usage by converting the print statements to the more robust dart:developer log function.

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PR created automatically by Jules for task 9198637711312378769 started by @LeanBitLab

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