wayland: Don't call gdk_display_sync()

It is not necessary.
Worse, it is reentrant and causes all sorts of avoc when processing
events halfway through initializing the context.

It only exists because in commit 3887548 the Wayland Vulkan code
was copy/pasted from X11.

Fixes #7022
Fixes #7025

gdk/wayland/gdkvulkancontext-wayland.c

@@ -40,13 +40,6 @@ gdk_wayland_vulkan_context_create_surface (GdkVulkanContext *context,
   GdkSurface *surface = gdk_draw_context_get_surface (GDK_DRAW_CONTEXT (context));
   GdkDisplay *display = gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context));
 
-  /* This is necessary so that Vulkan sees the Surface.
-   * Usually, vkCreateXlibSurfaceKHR() will not cause a problem to happen as
-   * it just creates resources, but further calls with the resulting surface
-   * do cause issues.
-   */
-  gdk_display_sync (display);
-
   return GDK_VK_CHECK (vkCreateWaylandSurfaceKHR, gdk_vulkan_context_get_instance (context),
                                                    &(VkWaylandSurfaceCreateInfoKHR) {
                                                        VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR,