This PR is a follow-up refactoring for #59376. It replaces
InvalidationCountingCacheWrapper with a simpler and more resuable
LockingAtomicCounter.

The change includes extracting the logic of "minimizing chance of caching stale
results" into a new class, which is now generic and not tied to any cache
related operations. This in turn allows it to be reused by different caches,
which often have subtle, important and anonying differences that make it
impossible (or at least cubersome and painful) to have a generic solution. So
this change of reducing the size of reusable code is the right move.

As an example of applying this new pattern, the caches for NativePrivilegeStore
are now migrated and managed by the centrialied CacheInvalidatorRegistry. The
clear privilege cache rest and transport actions are also updated to use the
new implementation. The Request/Response classes are intentionally untouched
and plan to have a separate PR to address them because they would involve user
visible deprecation changes.

Co-authored-by: Albert Zaharovits albert.zaharovits@elastic.co

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