Fix possible null pointers

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

@@ -73,6 +73,10 @@ public class FileSystemHelper {
             return null;
         }
 
+        if (model.getFileSystem() == null) {
+            return path;
+        }
+
         var shell = model.getFileSystem().getShell();
         if (shell.isEmpty()) {
             return path;

app/src/main/java/io/xpipe/app/storage/DataStorage.java

@@ -706,6 +706,10 @@ public abstract class DataStorage {
             return "?";
         }
 
+        if (!store.getValidity().isUsable()) {
+            return "?";
+        }
+
         return store.getProvider().browserDisplayName(store.getStore());
     }