layers: Remove extra 'no depth/stencil attachments exist' error
layers: Remove extra 'no depth/stencil attachments exist' error

This is now covered by other fairly clear errors.

Signed-off-by: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools