[MM-61771] Fix errcheck issues in server/channels/app/platform/service_test.go (#29375)

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

server/.golangci.yml

@@ -97,7 +97,6 @@ issues:
         channels/app/permissions_test.go|\
         channels/app/platform/helper_test.go|\
         channels/app/platform/license.go|\
-        channels/app/platform/service_test.go|\
         channels/app/platform/session.go|\
         channels/app/platform/status.go|\
         channels/app/platform/web_broadcast_hook.go|\