fix: Departments dropdown language toggle on Preview

[dsamojlenko]

Summary | Résumé

Fixes #3803

Added a key prop to the Combobox to force a refresh when toggling LanguagePriority on Preview.

To test:

• Create a form
• Add a Departments dropdown
• Go to Preview
• Check that the contents of the dropdown match the language of "Previewing in"
• Toggle the "Previewing in" language
• Check that the contents of the dropdown match the language of "Previewing in"

[github-actions[bot]]

:test_tube: Review environment

https://s7pfwx5y4taq67nrdxcoyvjdju0nsflj.lambda-url.ca-central-1.on.aws/