fix(aria): restore tab stop when active tab is removed

[abhisheksi-ngh]

Summary
Restore a valid tab stop when the active tab is removed after user interaction.
Preserve the current tab state when the active tab still exists.
Add a regression test to verify that the remaining tab receives tabindex="0" after the active tab is removed.

Testing
Test bundles compile successfully.
Browser tests could not run because the environment is missing libatk-1.0.so.0 and libgtk-3.so.0.

Related issue
Fixes #33961

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[abhisheksi-ngh]

@googlebot rescan
Hi maintainers, my Google Individual CLA is listed on the CLA website, and my commit uses the email associated with my GitHub account. However, the cla/google check still fails after requesting a rescan. Could you please verify my CLA association or advise on the next step? Thank you.