Fix geocode typo in Clipping Regions sandcastle

[jjspace]

Description

The Clipping regions sandcaslte was referencing an undefined variable because of a typo.

Issue number and link

Related to #12299

Testing plan

• Load the Clipping Regions sandcastle and make sure it loads

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

Thank you for the pull request, @jjspace!

✅ We can confirm we have a CLA on file for you.

[jjhembd]

Looks good, and I confirmed that the Sandcastle now works for me.
Thanks @jjspace!