CSS fix for 2FA token (#5000)

- Enforce white background for the QR code

InvenTree/templates/allauth_2fa/setup.html

@@ -14,7 +14,7 @@
   {% trans 'Scan the QR code below with a token generator of your choice (for instance Google Authenticator).' %}
 </p>
 
-<div class="bg-light rounded">
+<div class="bg-qr-code rounded">
 <img src="{{ qr_code_url }}" alt="{% trans 'QC Code' %}" class="mx-auto d-block"/>
 </div>
 <br>