shader_prepass is broken on main

[nicopap]

Bevy version

• 4d54ce1

AdapterInfo {
  name: "AMD Radeon RX 580 Series (RADV POLARIS10)",
  vendor: 4098, device: 26591,
  device_type: DiscreteGpu,
  driver: "radv", driver_info: "Mesa 23.0.3",
  backend: Vulkan
}

I ran cargo run --example shader_prepass, the example runs, but I get the following error. Also, when I press space bar, nothing happens (unlike previous commits, where it displayed the prepass buffers.

2023-05-09T11:51:41.379744Z ERROR bevy_render::render_resource::pipeline_cache: failed to process shader: 
error: Entry point fragment at Fragment is invalid
 = Argument 1 varying error
 = Capability MULTISAMPLED_SHADING is not supported

[mockersf]

Should be fixed by #8504