[release/3.6] 修复非 Windows 平台上游戏进程的 user.home 可能被设置为 null 的问题 (#4427)

https://github.com/HMCL-dev/HMCL/pull/4241

HMCLCore/src/main/java/org/jackhuang/hmcl/launch/DefaultLauncher.java

@@ -169,7 +169,7 @@ public class DefaultLauncher extends Launcher {
             }
 
             if (OperatingSystem.CURRENT_OS != OperatingSystem.WINDOWS)
-                res.addDefault("-Duser.home=", options.getGameDir().getParent());
+                res.addDefault("-Duser.home=", options.getGameDir().getAbsoluteFile().getParent());
 
             Proxy.Type proxyType = options.getProxyType();
             if (proxyType == null) {