Add Material/Card borderOnForeground flag to allow border to be painted behind the child widget (#27297)

In certain situations, a developer may require the border of a Material to be painted behind its child. For example a Card widget that has a full width image across the top half. In that scenario, the image should ideally be painted above the border with regards to z-position.

This change exposes a flag on Material widget to achieve this behavior. Additionally, the same flag is exposed on Card widget to allow the Card widget to pass this down to its Material.

I added a couple golden tests to verify this new behavior. Goldens are here:
https://github.com/flutter/goldens/commit/46a3d26acbb1b0d72b6b02c30f03b9dbda7d5bdf