[BUG] Cannot use Shift-Home and Shift-End

[JohanHeyvaert]

Describe the bug

Maybe not a real bug. :-)
It would be nice if one could use shift-home & shift-end in the search field. Just like in a standard textbox, in order to select text until start/end of the input.
I think the home and end keyboard events currently are intercepted by the options selection: first/last item is selected.

In combination with shift the home & end keys should not select first/last option but select input text.

To Reproduce

1. Open a select field that has mat-select-search
2. Type some text
3. Press SHIFT+HOME

Expected behavior
All input text should be selected. No item selection should be triggered.