TeaserV1.tsx: cssClass not properly constructed

When `props.isInEditor` equals to true, baseCssClass is not properly set:

https://github.com/adobe/aem-react-core-wcm-components-base/blob/bec40fd2ec0c413a37797e3a02835a349b41c79b/src/authoring/teaser/v1/TeaserV1.tsx#L88

Proposing to use:

`const cssClass = (props.isInEditor) ? props.baseCssClass + ' cq-dd-image' : props.baseCssClass;`

Start at src/authoring/teaser/v1/TeaserV1.tsx#L88, the location linked in the issue, and inspect how cssClass is constructed when props.isInEditor is true. Verify the resulting class value against the proposed behavior, then confirm the change preserves the existing value when the editor flag is false.

Written by the indexing model from the issue text.