Describe the bug

The class 'k-tabstrip' item is missing in the rendering of the TabStrip component.

To Reproduce

1. Go to the following demo and open the DevTools:

https://demos.telerik.com/blazor-ui/tabstrip/overview

2. Check the source of truth:

https://github.com/telerik/kendo-themes/blob/develop/tests/tabstrip/tabstrip.html 

Actual results

The class 'k-tabstrip-item' is missing.

Expected behavior

The class 'k-tabstrip-item' to be present.

Additional context

ThemeBuilder generates styles for the items of the TabStrip component with selectors like these:

.k-tabstrip .k-tabstrip-items-wrapper .k-tabstrip-items.k-reset.k-tabstrip-items-start .k-item.k-tabstrip-item.k-active .k-link

This works in other technologies, such as Kendo React, but it doesn't take effect in Blazor applications because of the issue.

Reported through t.1672526.