Fixes a crash when no mod folders are founded (#515)

* Fixes a crash when no mod folders are founded

Hi

* lemme

---------

Co-authored-by: ⍚~Nex <87421482+NexIsDumb@users.noreply.github.com>

source/funkin/backend/assets/ModsFolder.hx

@@ -93,7 +93,12 @@ class ModsFolder {
 	public static function getModsList():Array<String> {
 		var mods:Array<String> = [];
 		#if MOD_SUPPORT
-		for(modFolder in FileSystem.readDirectory(modsPath)) {
+		final modsList:Array<String> = FileSystem.readDirectory(modsPath);
+
+		if (modsList == null || modsList.length <= 0)
+			return mods;
+
+		for (modFolder in modsList) {
 			if (FileSystem.isDirectory('${modsPath}${modFolder}')) {
 				mods.push(modFolder);
 			} else {