Rubicon: Remove `buyeruid` logic

[SerhiiNahornyi]

@AntoxaAntoxic Please provide your review

[github-actions[bot]]

Code coverage summary

Note:

• Prebid team doesn't anticipate tests covering code paths that might result in marshal and unmarshal errors

• Coverage summary encompasses all commits leading up to the latest one, a39bc5a89b5ee282da27e77811b75e9e05e2f5a7

  rubicon

  Refer here for heat map coverage report

  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:183: resolveVideoSizeId          100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:201: appendTrackerToUrl          87.5%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:217: Builder                 100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:228: updateRequestTo26           92.3%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:253: MakeRequests                81.9%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:562: createImpsToExtMap          100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:581: prepareImpsToExtMap         100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:600: splitMultiFormatImp         61.5%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:637: resolveBidFloor             100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:645: updateImpRpTargetWithFpdAttributes  81.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:745: extractDfpAdUnitCode            100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:755: isNotKeyPathError           100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:759: addStringAttribute          100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:763: addStringArrayAttribute         100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:767: updateUserRpTargetWithFpdAttributes 70.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:797: updateExtWithIabAttribute       100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:806: populateFirstPartyDataAttributes    92.9%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:834: isStringArray               100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:844: isBoolArray             100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:854: convertToStringArray            100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:865: rawJSONToMap                100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:873: mapFromRawJSON              80.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:882: getSegmentIdsToCopy         100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:902: contains                75.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:911: isVideo                 100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:920: isFullyPopulatedVideo           100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:925: resolveNativeObject         88.2%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:957: setImpNative                82.4%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:986: MakeBids                92.2%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:1086:    mapImpIdToCpmOverride           90.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:1104:    resolveAdm              87.5%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:1119:    cmpOverrideFromBidRequest       100.0%
  github.com/prebid/prebid-server/v2/adapters/rubicon/rubicon.go:1128:    updateBidExtWithMetaNetworkId       82.4%
  total:                                  (statements)                85.1%