nullchecker fix for profileModel

app/src/main/java/awais/instagrabber/fragments/main/ProfileFragment.java

@@ -605,10 +605,12 @@ public class ProfileFragment extends Fragment implements SwipeRefreshLayout.OnRe
         }
         if (TextUtils.isEmpty(usernameTemp)) {
                 profileModel = appStateViewModel.getCurrentUser();
+            if (profileModel != null) {
                 username = profileModel.getUsername();
                 setUsernameDelayed();
                 setProfileDetails();
             }
+        }
         else if (isLoggedIn) {
             userService.getUsernameInfo(usernameTemp, new ServiceCallback<User>() {
                 @Override