Redesign TestSyncFlow

[pinebit]

🎯 Problem to be solved

Redesign and rebuild TestSyncFlow, likely from scratch user proper synchronization and timings. It was an annoying flakey test that was hard to reproduce locally, and it is currently disabled.

🛠️ Proposed solution

• All new TestSyncFlow implementation.

🧪 Tests

• Tested by new automated unit/integration/smoke tests