Clean up AnalyzeTextAsyncLROPoller logic before GA/next beta

During PR review (https://github.com/Azure/azure-sdk-for-python/pull/42685), reviewers flagged the complexity of the patched poller used to expose details in AnalyzeTextAsyncLROPoller (and the sync peer).
It should be relatively straightforward to patch a poller to expose the `details` property, and we should reduce paging complexity while preserving `ItemPaged/AsyncItemPaged` behavior.

Another refactor(PR: https://github.com/Azure/azure-sdk-for-python/pull/42928): Once the LRO finishes, should any actions still be “in progress”? If terminal LRO ⇒ in_progress should be 0, we likely shouldn’t surface this on the result page.

We’ll aim to simplify in the next beta or GA.