Guard slices from being requested by guest user

According to patch of A-231987122, AOSP restricts app to modify relevant
mobile settings when user is a guest. This change intends to prevent the
slices related to mobile settings from being requested by guest user.

Bug: 278616139
Bug: 277333776
Bug: 262244832
Bug: 278616520
Bug: 278615120
Test: robotests
Change-Id: I4dc4bbfdb5cf76e188e6f62ebfd74ef6fa2fe33b

src/com/android/settings/slices/SettingsSliceProvider.java

@@ -30,6 +30,7 @@ import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Binder;
 import android.os.StrictMode;
+import android.os.UserManager;
 import android.provider.Settings;
 import android.provider.SettingsSlicesContract;
 import android.text.TextUtils;
@@ -233,6 +234,14 @@ public class SettingsSliceProvider extends SliceProvider {
                 getContext().getTheme().rebase();
             }
 
+            // Checking if some semi-sensitive slices are requested by a guest user. If so, will
+            // return an empty slice.
+            final UserManager userManager = getContext().getSystemService(UserManager.class);
+            if (userManager.isGuestUser() && RestrictedSliceUtils.isGuestRestricted(sliceUri)) {
+                Log.i(TAG, "Guest user access denied.");
+                return null;
+            }
+
             // Before adding a slice to {@link CustomSliceManager}, please get approval
             // from the Settings team.
             if (CustomSliceRegistry.isValidUri(sliceUri)) {