Allow OT migration to auto write to fides preferences api

[eastandwestwind]

Closes https://ethyca.atlassian.net/browse/LJ-722

Description Of Changes

Allow OT migration to auto write to fides preferences api

Code Changes

• Adds code to automatically write to consent prefs api when we have OT consent
• Adds test assertions

Steps to Confirm

1. In fides-js-demo, uncomment out the window.fides_overrides declaration. Add a new field, ot_fides_mapping that will hold your OT -> fides mappings.
   Example core data:

{
    C0001: ["essential"],
    C0002: ["analytics"],
    C0004: ["advertising", "marketing"],
  }

To prep this, you'll need to JSON.stringify, then URL-encode it.
Here's my resulting fides_overrides obj:

window.fides_overrides = {
          fides_embed: true,
          ot_fides_mapping: "%7B%22C0001%22%3A%5B%22essential%22%5D%2C%22C0002%22%3A%5B%22analytics%22%5D%2C%22C0004%22%3A%5B%22advertising%22%2C%22marketing%22%5D%7D"
        };

3. Manually add the OT cookie to your browser. Below where you set the overrides, you'll need to set:

document.cookie =
             "OptanonConsent=isGpcEnabled=0&datestamp=Fri+Mar+07+2025+19%3A51%3A06+GMT%2B0100+(Central+European+Standard+Time)&version=202409.1.0&browserGpcFlag=0&isIABGlobal=false&hosts=&consentId=f9c105b8-48e3-401a-87e9-363ad1f77531&interactionCount=1&isAnonUser=1&landingPath=NotLandingPage&groups=C0003%3A1%2CC0002%3A1%2CC0004%3A1%2CC0005%3A0%2CC0001%3A1%2CC0009%3A0%2CV2STACK42%3A0&AwaitingReconsent=false";

Look at the groups param. Take that value and url-decode it. These groups map to either 0 (opted out) or 1 (opted in).
4. Based on our onetrust consent cookie and our mappings, we should see the essential / analytics / advertising / marketing notices opted-in by default, if they exist
5. We should see the fides_consent cookie written to the browser and consent vals should reflect the window.Fides.consent values. Note that the consent method in the cookie is "ot_migration"
6. We should see new entries in Consent Reporting in Admin UI for the "ot_migration" consent

Pre-Merge Checklist

• Issue requirements met
• All CI pipelines succeeded
• CHANGELOG.md updated
  • Add a db-migration This indicates that a change includes a database migration label to the entry if your change includes a DB migration
  • Add a high-risk This issue suggests changes that have a high-probability of breaking existing code label to the entry if your change includes a high-risk change (i.e. potential for performance impact or unexpected regression) that should be flagged
  • Updates unreleased work already in Changelog, no new entry necessary
• Followup issues:
  • Followup issues created
  • No followup issues
• Database migrations:
  • Ensure that your downrev is up to date with the latest revision on main
  • Ensure that your downgrade() migration is correct and works
    • If a downgrade migration is not possible for this change, please call this out in the PR description!
  • No migrations
• Documentation:
  • Documentation complete, PR opened in fidesdocs
  • Documentation issue created in fidesdocs
  • If there are any new client scopes created as part of the pull request, remember to update public-facing documentation that references our scope registry
  • No documentation updates required

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Name	Status	Preview	Comments	Updated (UTC)
fides-plus-nightly	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 2, 2025 3:30pm
fides-privacy-center	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 2, 2025 3:30pm

[gilluminate]

Looks good and works in testing. Thanks for updating to make it more maintainable through better abstraction! reminder to add a CHANGELOG entry :)

[cypress]

fides    Run #12892

Run Properties:   Passed #12892  •  de79ae0500: Allow OT migration to auto write to fides preferences api (#6099)

Project	fides
Branch Review	main
Run status	Passed #12892
Run duration	00m 56s
Commit	de79ae0500: Allow OT migration to auto write to fides preferences api (#6099)
Committer	Catherine Smith
View all properties for this run ↗︎

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Test results
Failures	0
Flaky	0
Pending	0
Skipped	0
Passing	5
View all changes introduced in this branch ↗︎