Viewer tabs no longer work as in 2.1.x

[CharlesGrimont]

Viewer tabs no longer behave as they did in the 2.1.x versions.

Current behavior:

• Tabs in viewer mode do not work as expected.
• Tab navigation or tab rendering behavior differs from 2.1.x.
• This can break forms relying on tabbed navigation in viewer mode.

Expected behavior:

• Viewer tabs should behave consistently with the 2.1.x behavior.
• Users should be able to navigate between tabs normally.
• Existing forms using tabs should remain compatible after upgrading.

Acceptance criteria:

• Viewer tab behavior is compared against 2.1.x.
• Tab navigation works correctly in viewer mode.
• Existing forms using tabs remain functional.
• No regression on editor or preview tab behavior.

[github-actions]

To be tested in 2.2.0-beta109

[gregory-vorbe]

OK in 2.2.0-beta112