[JS] Use a flywheel for struct row

When we access a row from a table or a struct, we create a proxy for the struct. We could improve the performance of these accesses by creating a single instance of the proxy and store it on the vector or the data type and then reuse that instance.

This should improve performance.

See https://github.com/apache/arrow/blob/7029f90ea3b39e97f1a671227ca932cbcdbcee05/js/src/visitor/get.ts#L219 and https://github.com/apache/arrow/blob/7029f90ea3b39e97f1a671227ca932cbcdbcee05/js/src/vector/struct.ts#L27.