fix: Scheme test errcheck issues (#28553)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/.golangci.yml

@@ -82,7 +82,6 @@ issues:
         channels/api4/role.go|\
         channels/api4/saml.go|\
         channels/api4/scheme.go|\
-        channels/api4/scheme_test.go|\
         channels/api4/shared_channel.go|\
         channels/api4/system.go|\
         channels/api4/system_local.go|\