DataGrid: make showEditorAlways cell editable in new row (T1323684)

[anna-shakhova]

No description provided.

[Copilot]

Pull request overview

This PR fixes DataGrid editing behavior so that showEditorAlways cells remain editable in newly inserted rows even when editing.allowUpdating is false, aligning getColumnTemplate logic with existing “new row can edit” behavior in click-to-edit handling.

Changes:

• Adjusts EditingControllerImpl.getColumnTemplate to treat row.isNewRow as editable for showEditorAlways cells when allowAdding is used but allowUpdating is disabled.
• Refactors readability of editability checks in getColumnTemplate (rowType/row state flags).
• Adds TestCafe coverage for editable showEditorAlways editors and boolean editors in new rows, plus a regression check for existing rows remaining readonly.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/devextreme/js/__internal/grids/grid_core/editing/m_editing.ts	Updates editor-template/editability gating to allow editing in inserted rows even when updating is disabled.
e2e/testcafe-devextreme/tests/dataGrid/common/editing/T1323684_readonlyEditorNewRow.ts	Adds end-to-end regression tests covering the new-row editable behavior and existing-row readonly behavior.