Tabs: overhaul unit tests (#66140)

* Rewrite unit tests

* Extract waitForComponentToBeInitializedWithSelectedTab utility function

* Use describe.each to run same test against controlled / uncontrolled components

* Re-enable tabs when testing disabled tabs

* Mock isRTL and test RTL keyboard navigation

* CHANGELOG

* Remove CHANGELOG entry

* Fix typo

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Co-authored-by: ciampo <[email protected]>
Co-authored-by: tyxla <[email protected]>