Fix flaky system-plus cypress test

[allisonking]

Closes N/A

Code Changes

• The call to update custom fields actually happens twice, one for each custom field that is being used. We were only intercepting one of the calls, and it wasn't consistent which call was intercepted, resulting in flaky failures. Now we intercept both calls and check both payloads.

Steps to Confirm

• CI passes, cypress passes locally

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

Description Of Changes

Write some things here about the changes and any potential caveats

[cypress]

Passing run #2271 ↗︎

0	4	0	0	0
⚠️ You've recorded test results over your free plan limit. Upgrade your plan to view test results.

Details:

Merge 26494c3 into 72df047...
Project: fides	Commit: fe02d9f94a ℹ️
Status: Passed	Duration: 00:47 💡
Started: May 31, 2023 3:19 PM	Ended: May 31, 2023 3:20 PM

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