[Teaser][List] getTeaserResource returns the image instead of the page

## Bug Report

**Current Behavior**
When using the List component in Teaser mode, delegating to Teaser v2, the resource is the feature image rather than the page.

**Expected behavior/code**
The resource should be the page like the current List items, and the teaser should have a working link URL.

**Environment**
- Core Components version 2.17.12

**Possible Solution**
Review getTeaserResource().

Start by locating and reading getTeaserResource() in the List component's Teaser v2 integration. Reproduce the List component in Teaser mode and verify that the returned resource is the page rather than its feature image. Done means the teaser uses the page resource and has a working link URL.

Written by the indexing model from the issue text.