iqzone get media type from mtype bid property

[IQZoneAdx]

Hi!
We need to support getting bid media type from seatbid.mtype

[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, a20b003

iqzone

Refer here for heat map coverage report

github.com/prebid/prebid-server/v2/adapters/iqzone/iqzone.go:19:	Builder		100.0%
github.com/prebid/prebid-server/v2/adapters/iqzone/iqzone.go:26:	MakeRequests	91.3%
github.com/prebid/prebid-server/v2/adapters/iqzone/iqzone.go:73:	makeRequest	77.8%
github.com/prebid/prebid-server/v2/adapters/iqzone/iqzone.go:93:	MakeBids	100.0%
github.com/prebid/prebid-server/v2/adapters/iqzone/iqzone.go:129:	getBidMediaType	100.0%
total:									(statements)	93.0%

[IQZoneAdx]

@Sonali-More-Xandr could you please pay your attention on my PR?