Blender Git Loki

Fix T92278: Small size of previews in the shading popover

Don't use the side padding for menu item contents when displaying
previews or icons in a row or grid layout. This can cause problems for
the preview drawing and doesn't make sense to draw there anyway.

This not only fixes the mentioned issue, but also too small heighlight
for the collection color tag in the Outliner context menu.

Alternative to and similar to D13125.