Share Paging Termination Between PagedFlux and PagedIterable

[alzimmermsft]

Description

Fixes #26064

This PR resolves an issue where PagedFlux and PagedIterable handled terminating the paged request stream based on the continuation token received as they have divergent logic to handle idiosyncrasies of async vs sync and the usage of Reactor. Now, PagedIterable will use the paging termination Predicate from the backing PagedFlux and pass that into the ContinuationState that is being maintained during the lifetime of a paged request stream. In this change ContinuationState now takes the Predicate as a constructor argument instead of being passed when the continuation token is being updated to better align with the requirement of having the Predicate. This has simplified the divergent logic between PagedFlux and PagedIterable to a constructor call instead of being in a few places where the ContinuationState is being updated.

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• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
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[reta]

Thanks a lot, @alzimmermsft !