Objective

Remove redundant manual synchronization logic for columnPositions in DevIndex.view.home.GridContainer.

Context

In an earlier attempt to fix #9195, manual logic was added to afterSetDataMode to update the columnPositions map.
The core issue has now been resolved in Neo.grid.column.Base (which handles the map update correctly and preserves order).
This application-level logic is now redundant and should be removed to keep the codebase clean.