Prevent crash

app/src/main/java/eu/faircode/email/FragmentCompose.java

@@ -3674,6 +3674,11 @@ public class FragmentCompose extends FragmentBase {
             db.message().liveMessage(id).observe(getViewLifecycleOwner(), new Observer<TupleMessageEx>() {
                 @Override
                 public void onChanged(TupleMessageEx draft) {
+                    if (draft == null) {
+                        dismiss();
+                        return;
+                    }
+
                     int plus = (draft.cc == null ? 0 : draft.cc.length) +
                             (draft.bcc == null ? 0 : draft.bcc.length);
                     tvTo.setText(MessageHelper.formatAddressesShort(draft.to) + (plus > 0 ? " +" + plus : ""));