[textanalytics] continuation_token does not work to rehydrate the LROs

[kristapratico]

We never documented this behavior/keyword, however a recent bug opened in .NET caused us to take a closer look at the implementation. As it is currently, we do not support rehydrating action or healthcare LROs, i.e. it will fail in the code.

For example, a user should not have to pass the input documents or actions to rehydrate the operation. We should allow dummy values being passed for these required parameters IF a continuation_token kwarg is passed. The complication is that the input documents and action order is used to order match the input with the output in TA. Without this information, we cannot guarantee ordering of our result.

Looking into customizing the polling method's get_continuation_token method to persist the ordering information so it can be used to recreate the expected result.