Fix scenario migration

The player may be created before the UI migrations have run, in which case we will attempt to update the filter buttons and fail utterly. Prevent this from happening.

resmon/ui.lua

@@ -107,6 +107,11 @@ end
 ---@param player LuaPlayer Whose filters are we updating?
 function ui_module.update_filter_buttons(player)
     local player_data = storage.player_data[player.index]
+    -- In extreme cases, the `player_data.ui` might not have been initialized yet (e.g., scenario from an old version)
+    if not player_data.ui then
+        return -- We cannot proceed in this case
+    end
+
     if not player_data.ui.active_filter then
         player_data.ui.active_filter = ui_module.FILTER_WARNINGS
     end