BitBucketServer [skip ci] feature doesn't work for automatic triggers

[vadlit]

BitBucketServer [skip ci] feature doesn't work for automatic triggers - commit comments are always empty nevertheless I see them in my repo.

I think the reason is here: there's no commit comment in the model - https://github.com/bitrise-io/bitrise-webhooks/blob/7e68fd767996abd0bd46df56a3058479f0f557f7/service/hook/bitbucketserver/bitbucketserver.go
And it's ok, because BitbucketServer really doesn't provide this information, it provides the hash only.

But then here https://github.com/bitrise-io/bitrise-webhooks/blob/7e68fd767996abd0bd46df56a3058479f0f557f7/service/hook/endpoint.go you don't even try to take commit comment from repo, you just pass it from the model to IsSkipBuildByCommitMessage. So it doesn't work for BitBucketServer