fix folder thumbnail appereance

Signed-off-by: alperozturk <alper_ozturk@proton.me>

app/src/main/res/drawable/ic_folder_offline.xml

@@ -0,0 +1,16 @@
+<!--
+  ~ Nextcloud - Android Client
+  ~
+  ~ SPDX-FileCopyrightText: 2018-2024 Google LLC
+  ~ SPDX-License-Identifier: Apache-2.0
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="@color/grey_600"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+    <path
+        android:fillColor="@color/grey_600"
+        android:pathData="M10,4H4c-1.1,0 -1.99,0.9 -1.99,2L2,18c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2V8c0,-1.1 -0.9,-2 -2,-2h-8l-2,-2z" />
+</vector>