Increase max default buffer size to 1 MiB

Increasing the max default buffer size prevents clients from crashing
when they need more than 4096 bytes. This can happen when the GUI thread
of the application is blocked, especially when moving your mouse over it
with high mouse sensitivity.

sway/server.c

@@ -222,6 +222,7 @@ bool server_init(struct sway_server *server) {
 	server->wl_event_loop = wl_display_get_event_loop(server->wl_display);
 
 	wl_display_set_global_filter(server->wl_display, filter_global, NULL);
+	wl_display_set_default_max_buffer_size(server->wl_display, 1024 * 1024);
 
 	root = root_create(server->wl_display);