Revert changes to inline assist indentation logic and prompt (#16403)

This PR reverts #16145 and subsequent changes.

This reverts commit a515442a365229155cde3de946e1b3eb244c0d36.

We still have issues with our approach to indentation in Python
unfortunately, but this feels like a safer equilibrium than where we
were.

Release Notes:

- Returned to our previous prompt for inline assist transformations,
since recent changes were introducing issues.