NullPointerException in ObservationViewerFragment

[kueda]

https://console.firebase.google.com/u/0/project/inaturalist-ios/crashlytics/app/android:org.inaturalist.android/issues/9204e0f44794199df7d12fd7eafa04ad

Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
       at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:121)
       at org.json.JSONTokener.nextValue(JSONTokener.java:98)
       at org.json.JSONObject.<init>(JSONObject.java:168)
       at org.json.JSONObject.<init>(JSONObject.java:185)
       at org.inaturalist.android.ObservationViewerFragment$PhotosViewPagerAdapter.instantiateItem(ObservationViewerFragment.java:520)