Fix T97159: AOV Pass in Cycles always gets Alpha Value of 1 for whole image

As far as I can see, it makes a lot of sense to have the alpha channel here, it matches the 2.x behavior and also matches what Eevee is doing.

Differential Revision: https://developer.blender.org/D14595

intern/cycles/kernel/svm/aov.h

@@ -32,7 +32,7 @@ ccl_device void svm_node_aov_color(KernelGlobals kg,
                                           kernel_data.film.pass_stride;
     ccl_global float *buffer = render_buffer + render_buffer_offset +
                                (kernel_data.film.pass_aov_color + node.z);
-    kernel_write_pass_float3(buffer, make_float3(val.x, val.y, val.z));
+    kernel_write_pass_float4(buffer, make_float4(val.x, val.y, val.z, 1.0f));
   }
 }