Issue Summary

If a bootstrap 5 bundle is referenced in the custom HTML header, it will break the unsubscribe action on the page.

Steps to Reproduce

1. Add the following custom header for the page:
   1<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/js/bootstrap.bundle.min.js" integrity="sha384-MrcW6ZMFYlzcLA8Nl+NtUVF0sA7MsXsP1UyJoMp4YLEuNSfAP+JcXn/tWtIaxVXM" crossorigin="anonymous"></script>
2. Create an email subscriber on the page
3. As the subscriber, attempt to unsubscribe

Expected Results

Subscriber can successfully unsubscribe

Actual Results

The unsubscribe button does not invoke any action, and there may be a console error for an "Illegal invocation"

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available