wayland: Fix the key level request layout parameter

Use the layout loop index instead of the current layout, which could be invalid if no layout event was received before the keymap event.

Fixes #13418

Author: Kontrabant

src/video/wayland/SDL_waylandevents.c

@@ -1435,7 +1435,7 @@ static void Wayland_KeymapIterator(struct xkb_keymap *keymap, xkb_keycode_t key,
     }
 
     for (xkb_layout_index_t layout = 0; layout < seat->keyboard.xkb.num_layouts; ++layout) {
-        const xkb_level_index_t num_levels = WAYLAND_xkb_keymap_num_levels_for_key(seat->keyboard.xkb.keymap, key, seat->keyboard.xkb.current_layout);
+        const xkb_level_index_t num_levels = WAYLAND_xkb_keymap_num_levels_for_key(seat->keyboard.xkb.keymap, key, layout);
         for (xkb_level_index_t level = 0; level < num_levels; ++level) {
             if (WAYLAND_xkb_keymap_key_get_syms_by_level(seat->keyboard.xkb.keymap, key, layout, level, &syms) > 0) {
                 /* If the keyboard is virtual or the key didn't have a corresponding hardware scancode, try to