Revert "Check for empty cardId in BarcodeSelectorActivity instead"

This reverts commit 62f7241bca.

app/src/main/java/protect/card_locker/BarcodeImageWriterTask.java

@@ -90,6 +90,11 @@ class BarcodeImageWriterTask extends AsyncTask<Void, Void, Bitmap>
 
     public Bitmap doInBackground(Void... params)
     {
+        if (cardId.isEmpty())
+        {
+            return null;
+        }
+
         MultiFormatWriter writer = new MultiFormatWriter();
         BitMatrix bitMatrix;
         try

app/src/main/java/protect/card_locker/BarcodeSelectorActivity.java

@@ -177,12 +177,6 @@ public class BarcodeSelectorActivity extends AppCompatActivity
             }
         });
 
-        if (cardId.isEmpty())
-        {
-            image.setVisibility(View.GONE);
-            return;
-        }
-
         if(image.getHeight() == 0)
         {
             // The size of the ImageView is not yet available as it has not