Add IsLoaded check to PawnIo.Close() method to prevent closing invalid handles (#1916)

* Initial plan

* Add IsLoaded check to PawnIo.Close() method to prevent closing invalid handles

Co-authored-by: PhyxionNL <7643972+PhyxionNL@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: PhyxionNL <7643972+PhyxionNL@users.noreply.github.com>