feat: add wait for first sync

[DominicGBauer]

Description

Add public waitForFirstSync function that will only resolve after the first sync

Work Done

• Added waitForFirstSync function to PowerSyncDatabaseImpl and PowerSyncDatabase interface
• Fixed issue in SyncStatus output where a colon should have been an equals sign

Testing

Added waitForFirstSync before and after updateHasSynced function.

1. If it is placed before then it stops the app as hasSynced is never updated.
2. If its placed afterwards then the app continues as expected.

[stevensJourney]

Just checking here:
"If it is placed before then it stops the app as hasSynced is never updated."
It might be confusing me since updateHasSynced is an internal function. The testing methodology here might be modifying the SDK behaviour.

In normal conditions, does the hasSynced eventually update to true when the lastSyncedAt updates? This should eventually cause waitForFirstSync to resolve.

[DominicGBauer]

Yes waitForFirstSync resolves after hasSynced has been updated.

[mugikhan]

LGTM