Updating ARF packages to 4.1.0-preview.6.

Packages/manifest.json

     "com.unity.test-framework": "1.1.16",
     "com.unity.textmeshpro": "3.0.1",
     "com.unity.ugui": "1.0.0",
-    "com.unity.xr.arcore": "4.1.0-preview.5",
-    "com.unity.xr.arfoundation": "4.1.0-preview.5",
-    "com.unity.xr.arkit": "4.1.0-preview.5",
-    "com.unity.xr.arkit-face-tracking": "4.1.0-preview.5",
+    "com.unity.xr.arcore": "4.1.0-preview.6",
+    "com.unity.xr.arfoundation": "4.1.0-preview.6",
+    "com.unity.xr.arkit": "4.1.0-preview.6",
+    "com.unity.xr.arkit-face-tracking": "4.1.0-preview.6",
     "com.unity.xr.interaction.toolkit": "0.9.4-preview",
     "com.unity.modules.ai": "1.0.0",
     "com.unity.modules.androidjni": "1.0.0",