* Add placeholder image for product preview
This adds the designated placeholder image url from settings into the
wcSettings global for the blocks to use. Then uses the placeholder url
when a product doesn't have any images.
* Updated based on review notes
Using `$block_settings` instead of `$settings`
Using '' alt tag
Updated snapshot
* Add the placeholder global to test that it passes through to the preview
renovate[bot]
Kevin Killingsworth
Kelly Dwan