osc: redraw on visibility option runtime changes

This affects behavior when using the "del" default key binding.
Sometimes, setting visibility to always did not draw it correctly. This
probably fixes it.

player/lua/osc.lua

@@ -2672,6 +2672,7 @@ function visibility_mode(mode, no_osd)
     end
 
     update_margins()
+    request_tick()
 end
 
 visibility_mode(user_opts.visibility, true)