Only list vendors in the data map as vendors_disclosed in the FE

[allisonking]

Bug Description

After another reread of the spec, we think it makes sense to only list the vendors in both the datamap and the GVL in the vendors_disclosed section of the TC string. See the discussion here: #4160 (comment)

The backend has gone ahead and made this change, so we should do something similar for the FE!

Steps to Reproduce

1. Set up your TCF environment
2. Opt in or opt out of all
3. Check your TC string—it'll have a huge vendors disclosed section since it lists every vendor in the GVL when it should really only list the vendors we are showing in the vendor tab.

Expected behavior

The vendors disclosed section should only show the vendors in the vendor tab.

Screenshots

If applicable, add screenshots to help explain your problem.

Environment

• Version:
• OS:
• Python Version:
• Docker Version:

Additional context

Add any other context about the problem here.

[allisonking]

Actually, it looks like we should not be including this string at all when the CMP API surfaces it
🤔 https://ethyca.slack.com/archives/C05E74TR0BB/p1696341554803559

[allisonking]

digging into the iab-tcf library some more, it looks like there is a requirement for when isServiceSpecific is false, to set all vendorsDisclosed https://github.com/InteractiveAdvertisingBureau/iabtcf-es/blob/0b1e3a6875b6e1dbff25845cb4ec83f5cc9c7264/modules/core/test/TCString.test.ts#L60

EDIT: actually, we set isServiceSpecific to true, so that shouldn't affect it...

[allisonking]

Okay we no longer surface the vendors_disclosed string as part of the CMP API: https://github.com/ethyca/fides/pull/4244/files

However, I am still confused about how to actually properly set the vendors_disclosed string, as the library seems to insist that we set all the GVL vendors. more investigation needed!