Fix 'Documents & other' missing problem am: 03b1b23c74

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/17910929

Change-Id: I846b255fa2e88e16c92799ad6e6f63cb8ddbbb9b
Ignore-AOSP-First: this is an automerge
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

src/com/android/settings/deviceinfo/storage/StorageItemPreferenceController.java

@@ -234,7 +234,9 @@ public class StorageItemPreferenceController extends AbstractPreferenceControlle
 
         // If isValidPrivateVolume() is true, these preferences will become visible at
         // onLoadFinished.
-        if (!isValidPrivateVolume()) {
+        if (isValidPrivateVolume()) {
+            mIsDocumentsPrefShown = isDocumentsPrefShown();
+        } else {
             setPrivateStorageCategoryPreferencesVisibility(false);
         }
     }