Add fallback for log truncation issue in Delta source

[vinishjail97]

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• Please ensure the GitHub issue is mentioned at the beginning of the PR

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• Fixed JSON parsing error when persisting state
• Added unit tests for schema evolution

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[brishi19791]

3rd #argument seems to be "mustBeRecreatable" and is false. if we just make this to true wont it be enough?

[vinishjail97]

Closing this draft PR.

The approach here — calling deltaLog.getChanges() to probe for vacuumed commit files — is reasonable in intent but has a meaningful downside: it eagerly opens and partially iterates the commit log on every incremental sync safety check, adding unnecessary I/O overhead on the hot path. As @brishi19791 noted, there may be a simpler fix via the mustBeRecreatable flag on getActiveCommitAtTime.

Additionally, the PR body was never filled out and the implementation was left as a draft without tests. Given it has been idle for ~3 months with the approach still in question, closing for now.

If the VACUUM-induced log truncation issue resurfaces, the fix should come with a clear description of the failure scenario, a unit/integration test that reproduces it, and a more targeted approach (e.g., verifying the mustBeRecreatable flag behavior or checking log file existence directly without iterating changes).