Fix for notifications not disappearing

[brianhogg]

Description

Fix escaping of the data attributes on a notification. Leaves the atts data intact in case someone has overridden notifications/basic.php and is expecting it to be there.

Fixes #2772

How has this been tested?

Checklist:

• [ ] This PR requires and contains at least one changelog file. <!-- To create a changelog yml file: npm run dev changelog add -- -i and follow the prompt. See also: https://github.com/gocodebox/lifterlms/blob/trunk/packages/dev/README.md#changelog-add -->
• [ ] My code has been tested.
• [ ] My code passes all existing automated tests.
• [ ] My code follows the LifterLMS Coding & Documentation Standards.