fix: handle boolean values in dataset preview

[Felipedino]

This pull request makes a small adjustment to the PreviewDatasetTable component to improve how boolean values are displayed in the dataset preview table.

• Now, boolean values in table cells are explicitly converted to strings for display, ensuring they render correctly in the UI.

[Copilot]

Pull request overview

This PR updates the PreviewDatasetTable dataset preview UI to ensure boolean cell values render visibly by converting booleans to strings during cell rendering.

Changes:

• Adds explicit boolean-to-string conversion when rendering table cell values.
• Refactors the column Cell renderer so image rendering and boolean formatting are handled in one place, with image columns still getting a fixed size.

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