Improve table selection

[JiuqingSong]

1. In table, when press TAB key to move focus to the next cell, if the cell is empty, collapse the selection
2. In last table cell, when press TAB key, no matter if there is text selected, always create a new table row

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After:

[Copilot]

Pull Request Overview

This PR improves table navigation behavior when using the TAB key to move between cells. It ensures that when navigating to an empty cell, the selection is collapsed to the start of the cell, and when pressing TAB in the last cell, a new row is always created regardless of the current selection state.

• Removes the collapsed selection check when determining if TAB should trigger table navigation
• Adds logic to collapse selection when moving to empty table cells

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/roosterjs-content-model-plugins/lib/edit/EditPlugin.ts	Removes collapsed selection requirement for table TAB navigation
packages/roosterjs-content-model-core/lib/corePlugin/selection/SelectionPlugin.ts	Adds selection collapse logic for empty table cells

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