T1319739 - DataGrid - Columns are misaligned after adding a column at runtime

[Raushen]

No description provided.

[Copilot]

Pull request overview

This PR fixes a bug (T1319739) where DataGrid columns become misaligned after adding or removing a column at runtime when repaintChangesOnly is enabled. The fix ensures that a full repaint is triggered when the column count changes, preventing header and data cell misalignment.

Changes:

• Extracted repaint logic into a new needFullRepaint method in the data controller
• Added detection for column count changes to trigger full repaint
• Added integration tests for both adding and removing columns with repaintChangesOnly=true

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/devextreme/js/__internal/grids/grid_core/data_controller/m_data_controller.ts	Adds needFullRepaint method to detect when full grid repaint is needed, including when column count changes
packages/devextreme/js/__internal/grids/grid_core/columns_controller/__tests__/columns_controller.integration.test.ts	Adds integration tests verifying that adding/removing columns maintains correct alignment between headers and data cells