[C++] Handle nulls consistently in set membership tests (Substrait <--> Acero)

[ianmcook]

Describe the bug, including details regarding any error messages, version, and platform.

There is a TODO here:

arrow/cpp/src/arrow/engine/substrait/expression_internal.cc

Line 1284 in 3c013da

// TODO(GH-36420) Acero does not currently handle nulls correctly

Now that #36739 is merged, can we use the new INCONCLUSIVE null matching option to translate Substrait SingularOrList expressions to/from Acero is_in function options with consistent null handling behavior?

Can we also use this new option to ensure that Substrait's index_in function is translated to/from Acero's index_in function with the correct options set to give consistent behavior?

Some other related issues:

• [C++] Convert SingularOrList to is_in when possible #36535
• Should we add an is_in function? substrait-io/substrait#517

Component(s)

C++