8509d78734
## Description This PR fixes the DatePicker overlay colors for the selected days. Before this PR, overlays were obscured by the selected day backgound. This fix simply replaces a DecoratedBox with an Ink to make the overlays visible. Combined with https://github.com/flutter/flutter/pull/159072 which fixes InkWell overlay color resolution related to the selected state, this PR fixes [Date picker overlay colors aren't applied on MaterialState.selected state](https://github.com/flutter/flutter/issues/130586). Before, no overlay visible for the selected day when hovered, focused, or pressed: https://github.com/user-attachments/assets/944d5035-68b2-40da-b606-3e8795229767 After, overlay is visible for the selected day when hovered, focused, or pressed (color change is slight as defined with M3 defaults): https://github.com/user-attachments/assets/2627955b-f45a-465f-8eb0-21955ccd8c3e ## Related Issue Fixes [Date picker overlay colors aren't applied on MaterialState.selected state](https://github.com/flutter/flutter/issues/130586). ## Tests Adds 12 tests. Updates several existing tests (those tests were looking for a `DecoratedBox`, make them look for an `Ink`).