Change user name query

app/src/main/java/io/xpipe/app/browser/OpenFileSystemCache.java

@@ -32,7 +32,7 @@ public class OpenFileSystemCache {
     public void init() throws Exception {
         ShellControl sc = model.getFileSystem().getShell().get();
         ShellDialect d = sc.getShellDialect();
-        username = sc.executeSimpleStringCommand(d.getPrintVariableCommand(d.getUsernameVariableName()));
+        username = d.printUsernameCommand(sc).readStdoutOrThrow();
     }
 
     public boolean isRoot() {

core/src/main/java/io/xpipe/core/process/ShellDialect.java

@@ -137,7 +137,7 @@ public interface ShellDialect {
 
     String getPrintVariableCommand(String name);
 
-    String getUsernameVariableName();
+    CommandControl printUsernameCommand(ShellControl shellControl);
 
     String getPrintExitCodeCommand(String prefix, String suffix);