fix go-vet errors related to privacy/enforcer

[onkarvhanumante]

• Activities framework #2844 made some changes to privacy/enforcer. This feature is in development so some code paths were intentionally made unreachable.
• However, this resulted in following go vet error:

  % (go vet ./... 2>&1) | grep -v -E "composite literal uses unkeyed fields"
   # github.com/prebid/prebid-server/adapters/adoppler
   # github.com/prebid/prebid-server/amp
   # github.com/prebid/prebid-server/endpoints/info
   # github.com/prebid/prebid-server/endpoints/events
   # github.com/prebid/prebid-server/endpoints
   # github.com/prebid/prebid-server/privacy
   privacy/enforcer.go:41:2: unreachable code
  

• The go vet check from PR tests is broken. So above error was never reported on PR. Refer fix errors reported by go vet  #2954 for more details.
• Plan is to fix go vet check. But before implementing fix, let's address any previously uncaught errors or warnings.

[VeronikaSolovei9]

Onkar, thank you for this PR!
May you please re-check the latest master to make sure this issue is not reproducible after we merged FPD/GEO PR: #2906

[onkarvhanumante]

Onkar, thank you for this PR! May you please re-check the latest master to make sure this issue is not reproducible after we merged FPD/GEO PR: #2906

Ran checks on updated master. #2906 fixes the go vet error of privacy/enforcer. Changes from this PR are no longer needed.

[VeronikaSolovei9]

Thank you