[Gantt] Binding the component to an empty array breaks the timeline header UI in Week view

[georgi-sla]

Describe the bug Currently, when the developer renders the Gantt in a Week view and binds it to an empty array, the timeline headers of the component display just a section from a specific week, and the UI is changed.

To Reproduce

1. Create a Gantt component.
2. Bind the component to an empty array.
3. Select the Week view.

Please, check out the following StackBlitz demo: https://stackblitz.com/edit/angular-iz4kwd

Expected behavior Binding the component to an empty array should not cause any UI modifications of the timeline header and the component should display the entire week:

Screenshots