FIx #122915: Diffuse normal input isn't normalized automatically

source/blender/gpu/shaders/material/gpu_shader_material_diffuse.glsl

@@ -7,7 +7,7 @@ void node_bsdf_diffuse(vec4 color, float roughness, vec3 N, float weight, out Cl
   ClosureDiffuse diffuse_data;
   diffuse_data.weight = weight;
   diffuse_data.color = color.rgb;
-  diffuse_data.N = N;
+  diffuse_data.N = safe_normalize(N);
 
   result = closure_eval(diffuse_data);
 }