Placeholder store removed, implemented creating default if none exist

src/App/UI/MainWindow/MainWindow.cs

@@ -32,7 +32,7 @@ public partial class MainWindow
             LoadDefaultShortcuts();
         }
 
-        passwordCollection = new PasswordList(passwordList);
+        passwordCollection = new PasswordList(passwordList, passwordStoreService);
     }
 
     private void SetSearchBarVisible(object sender, EventArgs e)