[client] overlay/status: don't return damage rect if nothing was drawn

The renderer contains an optimization to skip ImGui if there is nothing to
show, but the status overlay always returns a damage rect, even if it
didn't draw anything, so the optimization can never take effect.

client/src/overlay/status.c

@@ -89,6 +89,7 @@ static int status_render(void * udata, bool interactive, struct Rect * windowRec
   };
 
   int xPos = screen->x - marginX;
+  bool show = false;
   for(int i = 0; i < LG_USER_STATUS_MAX; ++i)
   {
     OverlayImage * img = &l_image[i];
@@ -99,6 +100,8 @@ static int status_render(void * udata, bool interactive, struct Rect * windowRec
     if (i == LG_USER_STATUS_RECORDING && !l_recordToggle)
       goto next;
 
+    show = true;
+
     ImDrawList_AddImage(
       igGetBackgroundDrawList_Nil(),
       img->tex,
@@ -118,6 +121,9 @@ static int status_render(void * udata, bool interactive, struct Rect * windowRec
     xPos -= ICON_SIZE + gapX;
   }
 
+  if (!show)
+    return 0;
+
   *windowRects = rect;
   return 1;
 }