[vulkan] Fix a missed lightmap stage for forward

This gets dynamic lights working again (well, minus the bad updates, I
need to figure out what's up there, but they're nothing new). I guess I
checked only for things running, not that dynamic lights worked.

libs/video/renderer/vulkan/rp_main_fwd.plist

@@ -1471,7 +1471,7 @@ steps = {
 			tasks = (
 				{ func = bsp_reset_queues; },
 				{ func = bsp_visit_world;
-				  params = (main); },
+				  params = (lightmap); },
 				{ func = scene_draw_viewmodel; },
 				//{ func = lighting_update_lights; },
 			);