Adagio: add Site to capabilities and correct error type

[linux019]

https://github.com/prebid/prebid-server-java/blob/master/src/main/resources/bidder-config/adagio.yaml#L17-L20

[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, 82312f6

adagio

Refer here for heat map coverage report

github.com/prebid/prebid-server/v3/adapters/adagio/adagio.go:20:	Builder		100.0%
github.com/prebid/prebid-server/v3/adapters/adagio/adagio.go:27:	MakeRequests	80.0%
github.com/prebid/prebid-server/v3/adapters/adagio/adagio.go:51:	MakeBids	93.8%
github.com/prebid/prebid-server/v3/adapters/adagio/adagio.go:114:	getBidType	100.0%
github.com/prebid/prebid-server/v3/adapters/adagio/adagio.go:129:	getBidExt	100.0%
total:									(statements)	92.6%

[osazos]

Hi @linux019,
#4590 was already opened for this purpose.
By the way, there was a specific reason we didn’t include the web capability (see #6327), so please avoid modifying our config file without checking with us first.

I acknowledge your point regarding the error type.

I suggest closing this PR and continuing with the initial one, #4590.