[Teaser] TeaserImpl tries to cast Asset to Page

[jckautzmann]

With the change that makes the Link Manager public (PR #2196) an incompatibility of the Teaser component to existing content was introduced. This affects Teasers that link to assets.

When configuring the main link with a link to an asset, opening the Teaser dialog throws following errors:

Caused by: java.lang.ClassCastException: class com.day.cq.dam.core.impl.AssetImpl cannot be cast to class com.day.cq.wcm.api.Page (com.day.cq.dam.core.impl.AssetImpl is in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @62c3e785; com.day.cq.wcm.api.Page is in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @f7b8f27)
    at com.adobe.cq.wcm.core.components.commons.editor.dialog.inherited.PageImageThumbnail.initModel(PageImageThumbnail.java:122)

When configuring the CTA with a link to an asset, rendering the page throws following errors:

Caused by: java.lang.ClassCastException: class com.day.cq.dam.core.impl.AssetImpl cannot be cast to class com.day.cq.wcm.api.Page (com.day.cq.dam.core.impl.AssetImpl is in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @62c3e785; com.day.cq.wcm.api.Page is in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoader @f7b8f27)
    at com.adobe.cq.wcm.core.components.internal.models.v1.TeaserImpl$Action.getCtaPage(TeaserImpl.java:513)
    at java.base/java.util.Optional.flatMap(Optional.java:294)
    at com.adobe.cq.wcm.core.components.internal.models.v2.TeaserImpl.getTargetPage(TeaserImpl.java:118)
    at com.adobe.cq.wcm.core.components.internal.models.v2.TeaserImpl.initImage(TeaserImpl.java:79)
    at com.adobe.cq.wcm.core.components.internal.models.v1.TeaserImpl.initModel(TeaserImpl.java:215)