feat(cdk/listbox): cdkOptionTypeaheadLabel should allow undefined

[spike-rabbit]

Feature Description

The input cdkOptionTypeaheadLabel of CdkOption should allow undefined as an input type

Use Case

I am using the cdkListbox internaly in a library. For this list, we allow users to provide an optional typeahead label.
When building the option I would like to write it like this:

<div [cdkOption]="value" [cdkOptionTypeaheadLabel]="optionalLabel">...</div>

However this is a compiler error. When adding an $any() cast everything works fine.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}