Adding nonce to course clone link

[brianhogg]

Description

Adding nonce to course clone link

How has this been tested?

Manually by visiting the url without the nonce, or with a different nonce key.

Types of changes

Security fix

Checklist:

• [x] 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 -->
• [x] My code has been tested.
• [ ] My code passes all existing automated tests.
• [x] My code follows the LifterLMS Coding & Documentation Standards.