Checks for nulls. Fixe issue

https://fabric.io/rocketchat3/android/apps/chat.rocket.android/issues/59b3f29bbe077a4dcc5c5fcd

app/src/main/java/chat/rocket/android/activity/MainActivity.java

@@ -95,6 +95,7 @@ public class MainActivity extends AbstractAuthedActivity implements MainContract
   }
 
   private void setupToolbar() {
+    if (pane != null) {
       pane.setPanelSlideListener(new SlidingPaneLayout.PanelSlideListener() {
         @Override
         public void onPanelSlide(View view, float v) {
@@ -119,13 +120,16 @@ public class MainActivity extends AbstractAuthedActivity implements MainContract
           }
         }
       });
+    }
 
+    if (toolbar != null) {
       toolbar.setNavigationOnClickListener(view -> {
         if (pane.isSlideable() && !pane.isOpen()) {
           pane.openPane();
         }
       });
     }
+  }
 
   private boolean closeSidebarIfNeeded() {
     // REMARK: Tablet UI doesn't have SlidingPane!