Add support for environment map transformation

[Soulghost]

Objective

• Fixes: https://github.com/bevyengine/bevy/issues/14036

Solution

• Add a world space transformation for the environment sample direction.

Testing

• I have tested the newly added transform field using the clearcoat example.
• By combining with the Add support for skybox transformation, we can rotate both the skybox and the environment light map to achieve the correct rendering effect.

 /// Spawns a camera with associated skybox and environment map.
 fn spawn_camera(commands: &mut Commands, asset_server: &AssetServer) {
+    let environment_rotation = Quat::from_rotation_y(PI * 0.125);
+
     commands
         .spawn(Camera3dBundle {
             camera: Camera {
@@ -224,11 +226,13 @@ fn spawn_camera(commands: &mut Commands, asset_server: &AssetServer) {
         .insert(Skybox {
             brightness: 5000.0,
             image: asset_server.load("environment_maps/pisa_specular_rgb9e5_zstd.ktx2"),
+            rotation: environment_rotation,
         })
         .insert(EnvironmentMapLight {
             diffuse_map: asset_server.load("environment_maps/pisa_diffuse_rgb9e5_zstd.ktx2"),
             specular_map: asset_server.load("environment_maps/pisa_specular_rgb9e5_zstd.ktx2"),
             intensity: 2000.0,
+            rotation: environment_rotation,
         });
 }

Original

Rotate by 22.5 degrees around the Y-axis

Migration Guide

• Since we have added a new filed to the EnvironmentMapLight struct, users will need to include ..Default::default() or some rotation value in their initialization code.