Palette search placeholders should be left-aligned

[CharlesGrimont]

Search placeholders in the palette element search bars should be left-aligned, including the JavaScript drag-and-drop palette.

Current behavior:

• Placeholder text in palette search inputs is not consistently left-aligned.
• The issue also affects the JavaScript drag-and-drop palette search field.
• This creates an inconsistent visual alignment in the editor UI.

Expected behavior:

• Search input text and placeholder text should be left-aligned in all palette search bars.
• The JavaScript drag-and-drop palette should use the same alignment as the regular element palette.
• Alignment should remain consistent across browsers.

Acceptance criteria:

• Placeholder text is left-aligned in the element palette search bar.
• Placeholder text is left-aligned in the JavaScript drag-and-drop palette search bar.
• Input text alignment remains consistent with the placeholder alignment.
• No regression on palette search behavior or filtering.

[github-actions]

To be tested in 2.2.0-beta107

[gregory-vorbe]

OK in 2.2.0-beta107

[gregory-vorbe]

Found another case:

Select Search bar:

[github-actions]

To be tested in 2.2.0-beta109

[gregory-vorbe]

OK in 2.2.0-beta112