Revert "osc.lua: draw box layout below console"

This reverts commit 2dd5bd4cd1.

Instead of drawing the box layout below any other overlay with z >= 0
which may not be wanted, the next commit will increase console's z only
in select mode instead.

player/lua/osc.lua

@@ -2502,7 +2502,7 @@ local function render()
 
     -- submit
     set_osd(osc_param.playresy * osc_param.display_aspect,
-            osc_param.playresy, ass.text, user_opts.layout == "box" and -1 or 1000)
+            osc_param.playresy, ass.text, 1000)
 end
 
 -- called by mpv on every frame