Refactor event image fallback

Instead of manually checking everywhere, return the first body's image
directly from the model if event has no image.

app/src/main/java/app/insti/adapter/FeedAdapter.java

@@ -113,11 +113,6 @@ public class FeedAdapter extends RecyclerView.Adapter<FeedAdapter.ViewHolder> {
 
         getSubtitle(viewHolder, currentEvent);
 
-        // Fallback to image of first body if event has no image
-        if (currentEvent.getEventImageURL() == null) {
-            currentEvent.setEventImageURL(currentEvent.getEventBodies().get(0).getBodyImageURL());
-        }
-
         if (currentEvent.isEventBigImage()) {
             viewHolder.eventBigPicture.setVisibility(View.VISIBLE);
             viewHolder.eventPicture.setVisibility(View.GONE);

app/src/main/java/app/insti/data/Event.java

@@ -112,6 +112,10 @@ public class Event {
     }
 
     public String getEventImageURL() {
+        // Fallback to body image if event has no image
+        if (eventImageURL == null) {
+            return getEventBodies().get(0).getBodyImageURL();
+        }
         return eventImageURL;
     }
 

app/src/main/java/app/insti/fragment/EventFragment.java

@@ -155,11 +155,6 @@ public class EventFragment extends BackHandledFragment {
         webEventButton = getActivity().findViewById(R.id.web_event_button);
         shareEventButton = getActivity().findViewById(R.id.share_event_button);
 
-        // Fallback to image of first body if event has no image
-        if (event.getEventImageURL() == null) {
-            event.setEventImageURL(event.getEventBodies().get(0).getBodyImageURL());
-        }
-
         Picasso.get().load(event.getEventImageURL()).into(eventPicture);
         eventTitle.setText(event.getEventName());
         Markwon.setMarkdown(eventDescription, event.getEventDescription());