Use ArrayView appender to simplify array construction in R and Python bindings

In https://github.com/apache/arrow-nanoarrow/pull/930 we implement an appender that can append an arbitrary ArrowArrayView storage to an ArrowArray in append mode. In the R and Python bindings we allow a schema request, and there are a few cases where we can probably use the appender to help.

This will also give some more realistic traffic to the new functions, so we can catch any other potential issues.

Start by reading the appender implementation in PR #930, then inspect the R and Python binding paths that handle schema requests. Identify the cases where the appender can replace existing array-construction logic, and verify that the new functions receive realistic binding traffic without changing current behavior.

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