fix(typeahead): keep overlay position fixed when scrolling

[ljanner]

See https://material.angular.dev/cdk/overlay/overview#scroll-strategies, fixes #1588

---

Documentation.
Examples.
Dashboards Demo.
Playwright report.

Coverage Reports:

• element-ng
• element-translate-ng

[gemini-code-assist]

Code Review

This pull request addresses an issue where the typeahead overlay would not maintain its position when the page is scrolled. The fix involves adding scrollStrategy: this.overlay.scrollStrategies.reposition() to the overlay configuration. This is the correct approach to ensure the overlay repositions itself relative to the input element during scroll events. The change is concise and effectively resolves the bug.

[ljanner]

Optimally need to find a way to test this behaviour.

[spliffone]

I am in favour of having the scroll strategy configurable, since we might need a different behaviour in filtered search oder other use cases.