fix(grid): Correct shift-click selection in grouped IgxGrid #13757

[valeriatoneva]

Closes #13757

This PR addresses the issue where shift-click was not functioning correctly in an IgxGrid with grouped rows. The selection logic has been updated to properly handle multi-level group comparisons, ensuring that the shift-click selection is consistent and intuitive in grouped grids.

Additional information:

• Bug fix
• New functionality
• Documentation
• Demos
• CI/CD

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code
• This PR includes API docs for newly added methods/properties
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes
• This PR includes behavioral changes and the feature specification has been updated with them

[hanastasov]

Please remove the changes from package, package-lock files, the forgotten console.logs, and formattings that appear in the file. Also, add unit test covering the scenario reported. The unit test should fail without the fix and pass with the fix.

After all of this you can open PR against 16.1.x, 17.0.x branches as well.