ConnectAd: String/int fix

[rtuschkany]

fix to support string and int values as SiteID/NetworkID

[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, 1932591

connectad

Refer here for heat map coverage report

github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:22:	Builder			100.0%
github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:29:	MakeRequests		95.0%
github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:73:	MakeBids		100.0%
github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:107:	preprocess		100.0%
github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:141:	addImpInfo		100.0%
github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:151:	addHeaderIfNonEmpty	100.0%
github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:157:	unpackImpExt		88.9%
github.com/prebid/prebid-server/v2/adapters/connectad/connectad.go:181:	buildImpBanner		100.0%
total:									(statements)		97.6%