Lacking compatibility with plugins that add new worlds

[jasonw4331]

❗️ Please describe the issue

Plugin Crashes when attempting to handle virtual worlds (Worlds without a dedicated world folder).

--- Stack trace ---

#0 pmsrc/src/utils/Config(246): pocketmine\utils\Filesystem::safeFilePutContents(string[45] /home/gs-40319/worlds/world nether/worlds.yml, string[11] --- [].....)

#1 pmsrc/src/utils/Config(166): pocketmine\utils\Config->save()

#2 pmsrc/src/utils/Config(121): pocketmine\utils\Config->load(string[45] /home/gs-40319/worlds/world nether/worlds.yml, integer -1, array[0])

#3 plugins/Worlds (4).phar/src/surva/worlds/Worlds(215): pocketmine\utils\Config->construct(string[45] /home/gs-40319/worlds/world nether/worlds.yml)

#4 plugins/Worlds (4).phar/src/surva/worlds/Worlds(150): surva\worlds\Worlds->getCustomConfig(string[45] /home/gs-40319/worlds/world nether/worlds.yml)

#5 plugins/Worlds (4).phar/src/surva/worlds/Worlds(65): surva\worlds\Worlds->registerWorld(string[12] world nether)

#6 pmsrc/src/plugin/PluginBase(137): surva\worlds\Worlds->onEnable()

#7 pmsrc/src/plugin/PluginManager(437): pocketmine\plugin\PluginBase->onEnableStateChange(true)

#8 pmsrc/src/Server(1385): pocketmine\plugin\PluginManager->enablePlugin(object surva\worlds\Worlds#25348)

#9 pmsrc/src/Server(1011): pocketmine\Server->enablePlugins(object pocketmine\plugin\PluginEnableOrder#24921)

#10 pmsrc/src/PocketMine(304): pocketmine\Server->construct(object BaseClassLoader#3, object pocketmine\utils\MainLogger#2, string[15] /home/gs-40319/, string[23] /home/gs-40319/plugins/)

#11 pmsrc/src/PocketMine(327): pocketmine\server()

#12 pmsrc(11): require(string[83] phar:///pro/bin/mcpe/pocketmine-1.18.10-4.2.0/PocketMine-MP.phar/src/PocketMine.)

--- End of exception information ---

✅ How should it usually work?

Plugin should operate normally

🗂 Steps to reproduce

1. Add a plugin that uses virtual worlds (like NativeDimensions)
2. Start the server

🌱 Environment

Version of this plugin: v3.1.1
Version of PocketMine-MP: 4.2.6