Allows CDN to cache empty experiences responses from fides.js API

[eastandwestwind]

Closes #4108

Description Of Changes

Updates experience API to return empty obj instead of undefined when no experience was found for a specific location. This allows cache to work properly under this scenario, meaning that requests to the server will decrease overall.

Code Changes

• Return empty obj for fides.js experience API when no experience was found
• Update e2e tests

Steps to Confirm

• Use a prefetch enabled privacy center and fides.js via the CDN. Ensure that debug mode is on.
• Ensure the location you are in does not have a valid privacy notice
• Go to the URL where fides.js is installed (i.e. Cookie House) and inspect the console
• View the line that starts with Got experience response from Fides API, returning: and see that {} is returned instead of being undefined or null.

Pre-Merge Checklist

• All CI Pipelines Succeeded
• Documentation:
  • documentation complete, PR opened in fidesdocs
  • documentation issue created in fidesdocs
• Issue Requirements are Met
• Relevant Follow-Up Issues Created
• Update CHANGELOG.md
• For API changes, the Postman collection has been updated

[cypress]

Passing run #4223 ↗︎

0	4	0	0	0
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Details:

Merge b211b53 into b770602...
Project: fides	Commit: 214046a081 ℹ️
Status: Passed	Duration: 01:09 💡
Started: Sep 19, 2023 4:22 PM	Ended: Sep 19, 2023 4:23 PM

_{This comment has been generated by cypress-bot as a result of this project's GitHub integration settings.}

[allisonking]

ah this is a tricky problem!!

can we try to make the types stricter? I think once we make it stricter, some other pieces will fall into place, and we might not need some of the helper methods 🤞 of course, TS can often be tricky, so maybe my theory won't pan out, but I think it's worth trying, and will be less likely to bite us in the future

[allisonking]

🎉