fix(z-input): remove clear and toggle password buttons from tab order

[ada-workbackai]

Summary

Fixes WCAG 2.1.1 (Keyboard) by removing the clear icon and show/hide password buttons from the keyboard tab order in z-input component.

Issue: The clear (×) button and show/hide password (eye icon) button were in the natural tab order, interrupting the flow between form fields and forcing keyboard users to tab through secondary actions.

Solution: Added tabindex="-1" to both buttons, removing them from keyboard tab sequence while keeping them accessible via mouse/touch and screen reader browse mode.

Test Plan

• Clear button and show/hide password button removed from tab order
• Buttons remain clickable via mouse/touch
• Buttons remain accessible to screen readers via browse mode
• Form field tab order flows naturally: field 1 → field 2 → submit button

Evidence

Part of the fix for: https://app.workback.ai/dashboard/issue/78/

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WCAG Reference:
2.1.1 Keyboard