Improve TestStateSyncerManager_EventTracker_Sync

[begmaroman]

Description

Improve TestStateSyncerManager_EventTracker_Sync by deploying currently hardcoded contract as an artifact instead. Delete related TODO from the code.
File: consensus/polybft/state_sync_manager_test.go

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually