Fix: Set region for prod testing

[zwilling]

yarn test:prod was failing with a Firebase: not-found error.
Setting the region for prod testing resolves it.

How Has This Been Tested?

• Running the unittests yarn test:prod

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (Is there something to change?)
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• I reviewed the code of conduct and contributors' guide