Fix column selector for Explorers and Converters.

[Irozuku]

Summary

This PR fixes the issue where the select all columns button in explorers/converters creation step was not considering columns not visible. Also updates default amount of rows from 5 to 10 on mount.

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Type of Change

Check all that apply like this [x]:

• Backend change
• Frontend change
• CI / Workflow change
• Build / Packaging change
• Bug fix
• Documentation

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Changes (by file)

Briefly list the important modified files and what was done.

• DashAI\front\src\components\notebooks\ColumnSelector.jsx: Added a handleSelectAllRows function to properly select all columns and update pagination rows visible on mount.

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Testing (optional)

• Verify that the select all button properly select all the columns including the ones not visible on the table.
• Verify that the select columns table renders showing 10 rows on mount.