Improve the implementation of InputIteratorTransformer

### Description

The current implementation of InputIteratorTransformer has an assert that the child must be ColumnarInputAdapter. We should do the assertion eagerly.

### Gluten version

main branch

Start by locating the InputIteratorTransformer implementation and inspect where it currently asserts that its child is a ColumnarInputAdapter. Determine how to move that assertion to the eager validation point, then run the relevant existing tests to confirm the transformer rejects invalid children as expected.

Written by the indexing model from the issue text.