Fix crash in MediaGalleryAlbumCursorWrapper

[kinnerapriyap]

Fatal Exception: java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String android.database.Cursor.getString(int)' on a null object reference
       at android.database.MergeCursor.getString(MergeCursor.java:98)
       at android.database.MergeCursor.getString(MergeCursor.java:98)
       at com.kinnerapriyap.sugar.mediagallery.album.MediaGalleryAlbumCursorWrapper.getString(MediaGalleryAlbumCursorWrapper.java:126)
       at com.kinnerapriyap.sugar.mediagallery.album.MediaGalleryAlbumCursorWrapper.getString(MediaGalleryAlbumCursorWrapper.java:123)
       at android.widget.SimpleCursorAdapter.bindView(SimpleCursorAdapter.java:150)
       at android.widget.CursorAdapter.getView(CursorAdapter.java:289)
       at android.widget.Spinner.measureContentWidth(Spinner.java:858)
       at android.widget.Spinner.onMeasure(Spinner.java:608)
       at androidx.appcompat.widget.AppCompatSpinner.onMeasure(AppCompatSpinner.java:428)
       at android.view.View.measure(View.java:23466)
       at androidx.appcompat.widget.Toolbar.measureChildCollapseMargins(Toolbar.java:1668)
       at androidx.appcompat.widget.Toolbar.onMeasure(Toolbar.java:1776)
       at android.view.View.measure(View.java:23466)
       at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
       at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
       at android.view.View.measure(View.java:23466)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6834)
       at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
       at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
       at android.view.View.measure(View.java:23466)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6834)
       at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1565)
       at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
       at android.widget.LinearLayout.onMeasure(LinearLayout.java:726)
       at android.view.View.measure(View.java:23466)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6834)
       at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
       at android.view.View.measure(View.java:23466)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6834)
       at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1565)
       at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
       at android.widget.LinearLayout.onMeasure(LinearLayout.java:726)
       at android.view.View.measure(View.java:23466)
       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6834)
       at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
       at com.android.internal.policy.DecorView.onMeasure(DecorView.java:847)
       at android.view.View.measure(View.java:23466)
       at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2954)
       at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1753)
       at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2041)
       at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1636)
       at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7946)
       at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1092)
       at android.view.Choreographer.doCallbacks(Choreographer.java:893)
       at android.view.Choreographer.doFrame(Choreographer.java:812)
       at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1078)
       at android.os.Handler.handleCallback(Handler.java:907)
       at android.os.Handler.dispatchMessage(Handler.java:105)
       at android.os.Looper.loop(Looper.java:216)
       at android.app.ActivityThread.main(ActivityThread.java:7625)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987)