Fix #122847: Show Transparent Render Pass

EEVEE has a transparent render pass that renders materials where
the render mode is set to blended. This was introduced when EEVEE-Next
was still in development, but was never fully backported.

This PR adds the missing pieces.

Pull Request: https://projects.blender.org/blender/blender/pulls/123298

scripts/startup/bl_ui/properties_view_layer.py

@@ -184,6 +184,7 @@ class VIEWLAYER_PT_eevee_next_layer_passes_light(ViewLayerButtonsPanel, Panel):
         col.prop(view_layer, "use_pass_environment")
         col.prop(view_layer, "use_pass_shadow")
         col.prop(view_layer, "use_pass_ambient_occlusion", text="Ambient Occlusion")
+        col.prop(view_layer_eevee, "use_pass_transparent", text="Transparent")
 
         col = layout.column()
         col.active = view_layer.use_pass_ambient_occlusion