Dataviews: Fix alignment issue of "Title" column header

[im3dabasia]

Closes: #68838

What?

This PR addresses the issue where the "Title" column header is not properly aligned in Dataviews when a titleField is set. The column header shifts to the left, misaligned with the search box above and the rows below.

Why?

The issue is caused by an extra margin-left on the dataviews-view-table-header.

How?

Removes the conflicting margin-left to restore proper header alignment.

Testing Instructions

1. Run npm run storybook.
2. Open the Dataviews story in Storybook.
3. Check the header alignment for the first column.
4. Ensure the "Title" column header is now properly aligned.

Screenshots

Before	After

[github-actions]

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Co-authored-by: im3dabasia <im3dabasia1@git.wordpress.org>
Co-authored-by: ecgan <ecgan@git.wordpress.org>

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