Embed block preview layout position is not fully aligned with block border.

Steps:
1. Go to Studio UI.
2. Create new Landing Page.
3. Add an Embed block.
4. Choose content "Media/Images/Visual travels".
5. Submit the settings form.
6. Examine the preview of the added content.
Actual: Preview image does not use the whole space of the block border.
Expected: Preview is aligned with the block border.

Remarks: Please see attached screen-shot.