[Button] Dynamically enabling/disabling the component breaks the keyboard navigation

[georgi-sla]

Describe the bug Currently, when the disabled state of the Button component is dynamically enabled/disabled, the keyboard navigation gets broken:

• a Button that is dynamically enabled is unreachable with the keyboard
• a Button that is dynamically disabled is still focusable with the keyboard

To Reproduce

1. Create two Button components (using the kendo-button selector) - one enabled and one disabled.
2. Dynamically update the disabled state of the two Buttons.

Please, check out the following StackBlitz demo: https://stackblitz.com/edit/angular-u9svkg-a9sft9

Expected behavior Dynamically updating the disabled state of the Button component should also update the keyboard navigation:

• a Button that is dynamically enabled should be focusable with the keyboard
• a Button that is dynamically disabled should be unreachable with the keyboard

Additional context From what I have noticed, it seems like the tabindex of the Button component is not dynamically updated.

[slavenai]

Reproducible with kendo-button and span[kendoButton]. Works as expected with button[kendoButton].

[dtopalov]

The kendo-button and span[kendoButton] approaches for creating a Button component are deprecated. Please use button[kendoButton] instead.