Connatix: support GPID

[karimMourra]

This PR includes the gpid from the incoming bid request, in the outgoing bid request.
Equivalent PR for PBS-JAVA

[github-actions]

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, 218a6de

connatix

Refer here for heat map coverage report

github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:24:	Builder			100.0%
github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:31:	MakeRequests		100.0%
github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:66:	MakeBids		95.0%
github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:106:	validateAndBuildImpExt	100.0%
github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:115:	splitRequests		90.9%
github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:195:	buildRequestImp		100.0%
github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:239:	buildDisplayManagerVer	88.9%
github.com/prebid/prebid-server/v3/adapters/connatix/connatix.go:257:	getBidType		100.0%
total:									(statements)		94.9%