Fixes #4993
added missing docblock
use TableGatewayInterface instead
remove check $feature->getTableGateway() instance of TableGatewayInterface
Merge branch 'hotfix/5887-master'

Close #5887
Fixes #5228
Merge pull request #5868 from samsonasik/featureset.tablegateway

Fixes #4993
Merge branch 'hotfix/5868' into develop

Forward port #5868