wayland: Attach EGL objects to custom and external surfaces during reconfiguration

They are required when using EGL with an external surface.

(cherry picked from commit 06795b00ad7a51f13c5cc9393157680b7c7f186e)

src/video/SDL_video.c

@@ -2662,11 +2662,6 @@ static bool SDL_ReconfigureWindowInternal(SDL_Window *window, SDL_WindowFlags fl
         return false;
     }
 
-    // Don't attempt to reconfigure external windows.
-    if (window->flags & SDL_WINDOW_EXTERNAL) {
-        return false;
-    }
-
     // Only attempt to reconfigure if the window has no existing graphics flags.
     if (window->flags & (SDL_WINDOW_OPENGL | SDL_WINDOW_METAL | SDL_WINDOW_VULKAN)) {
         return false;

src/video/wayland/SDL_waylandwindow.c

@@ -2654,7 +2654,9 @@ bool Wayland_ReconfigureWindow(SDL_VideoDevice *_this, SDL_Window *window, SDL_W
 {
     SDL_WindowData *data = window->internal;
 
-    if (data->shell_surface_status == WAYLAND_SHELL_SURFACE_STATUS_SHOWN) {
+    // Don't try to reconfigure mapped windows, unless they are custom or external.
+    if (data->shell_surface_status == WAYLAND_SHELL_SURFACE_STATUS_SHOWN &&
+        data->shell_surface_type != WAYLAND_SHELL_SURFACE_TYPE_CUSTOM) {
         // Window is already mapped; abort.
         return false;
     }