[Bug][Dialog] Selectors for predefined dialogs are not rendered

[filipKovachev]

Describe the bug Currently, we have classNames for predefined dialogs that are not rendered in the component markup: .k-dialog.k-prompt,.k-dialog.k-alert,.k-dialog.k-confirm

https://www.telerik.com/kendo-vue-ui/components/dialogs/dialog/accessibility-docs/wai-aria-support/#toc-predefined-dialogs

To Reproduce Open this StackBlitz and notice that the selectors mentioned in our article are not rendered: https://stackblitz.com/edit/8yb7hd?file=src%2Fmain.vue

Expected behavior The .k-dialog.k-prompt,.k-dialog.k-alert,.k-dialog.k-confirm should be rendered

Reported in Ticket ID: 1641064