build: Pin django-user-tasks.

The latest version only works with Django 5.2 so we'll either need to
fix that or just wait till we're ready to do that bump.

Author: feanil

requirements/constraints.txt

@@ -158,3 +158,8 @@ social-auth-core==4.5.4
 # Issue: https://github.com/openedx/edx-platform/issues/36695
 lxml==5.3.2
 xmlsec==1.3.14
+
+# Date 2025-05-09
+# Pin django-user-tasks because the newest version is not compatible with Django 4.2
+# Issue: https://github.com/openedx/edx-platform/issues/36696
+django-user-tasks==3.3.0